Move the authoritative source for functions from the man page to various

.xml files (some new, some updated) next to the modules that implement
them.  Generate the man page using the output generated from the .xml
file by bin/scons-proc.py.

2 files changed, 23 insertions, 4044 deletions

diff --git a/doc/SConscript b/doc/SConscript
index e22aec0..ffffe59 100644
--- a/doc/SConscript
+++ b/doc/SConscript
@@ -403,11 +403,11 @@ for m in man_page_list:
     x = orig_env.SCons_revision(os.path.join(build, 'man', m),
                             os.path.join('man', m))
 
-man_i_files = ['builders.man', 'tools.man', 'variables.man']
+man_i_files = ['builders.man', 'functions.man', 'tools.man', 'variables.man']
 
 man_intermediate_files = [os.path.join(build, 'man', x) for x in man_i_files]
 
-cmd = "$PYTHON $SCONS_PROC_PY --man -b ${TARGETS[0]} -t ${TARGETS[1]} -v ${TARGETS[2]} $( $SOURCES $)"
+cmd = "$PYTHON $SCONS_PROC_PY --man -b ${TARGETS[0]} -f ${TARGETS[1]} -t ${TARGETS[2]} -v ${TARGETS[3]} $( $SOURCES $)"
 man_intermediate_files = env.Command(man_intermediate_files,
                                      scons_doc_files,
                                      cmd)
diff --git a/doc/man/scons.1 b/doc/man/scons.1
index be0abe3..5d3cfd9 100644
--- a/doc/man/scons.1
+++ b/doc/man/scons.1
@@ -2393,4055 +2393,34 @@ and global functions supported by
 include:
 
 '\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Action( action ", [" cmd/str/fun ", [" var ", ...]] [" option = value ", ...])"
-.TP
-.IR env .Action( action ", [" cmd/str/fun ", [" var ", ...]] [" option = value ", ...])"
-Creates an Action object for
-the specified
-.IR action .
-See the section "Action Objects,"
-below, for a complete explanation of the arguments and behavior.
-
-Note that the
-.BR env.Action ()
-form of the invocation will expand
-construction variables in any argument strings,
-including the
-.I action
-argument, at the time it is called
-using the construction variables in the
-.I env
-construction environment through which
-.BR env.Action ()
-was called.
-The
-.BR Action ()
-form delays all variable expansion
-until the Action object is actually used.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AddMethod( object, function ", [" name ])
-.TP
-.RI env.AddMethod( function ", [" name ])
-When called with the
-.BR AddMethod ()
-form,
-adds the specified
-.I function
-to the specified
-.I object
-as the specified method
-.IR name .
-When called with the
-.BR env.AddMethod ()
-form,
-adds the specified
-.I function
-to the construction environment
-.I env
-as the specified method
-.IR name .
-In both cases, if
-.I name
-is omitted or
-.BR None ,
-the name of the
-specified
-.I function
-itself is used for the method name.
-
-Examples:
-
-.ES
-# Note that the first argument to the function to
-# be attached as a method must be the object through
-# which the method will be called; the Python
-# convention is to call it 'self'.
-def my_method(self, arg):
-    print "my_method() got", arg
-
-# Use the global AddMethod() function to add a method
-# to the Environment class.  This
-AddMethod(Environment, my_method)
-env = Environment()
-env.my_method('arg')
-
-# Add the function as a method, using the function
-# name for the method call.
-env = Environment()
-env.AddMethod(my_method, 'other_method_name')
-env.other_method_name('another arg')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AddOption( arguments )
-This function adds a new command-line option to be recognized.
-The specified
-.I arguments
-are the same as supported by the standard Python
-.BR optparse.add_option ()
-method (with a few additional capabilities noted below);
-see the documentation for
-.B optparse
-for a thorough discussion of its option-processing capabities.
-
-In addition to the arguments and values supported by the
-.B optparse.add_option ()
-method,
-the SCons
-.BR AddOption ()
-function allows you to set the
-.B nargs
-keyword value to
-.B '?'
-(a string with just the question mark)
-to indicate that the specified long option(s) take(s) an
-.I optional
-argument.
-When
-.B "nargs = '?'"
-is passed to the
-.BR AddOption ()
-function, the
-.B const
-keyword argument
-may be used to supply the "default"
-value that should be used when the
-option is specified on the command line
-without an explicit argument.
-
-If no
-.B default=
-keyword argument is supplied when calling
-.BR AddOption (),
-the option will have a default value of
-.BR None .
-
-Once a new command-line option has been added with
-.BR AddOption (),
-the option value may be accessed using
-.BR GetOption ()
-or
-.BR env.GetOption ().
-'\" NOTE: in SCons 1.x or 2.0, user options will be settable, but not yet.
-'\" Uncomment this when that works.  See tigris issue 2105.
-'\" The value may also be set, using
-'\" .BR SetOption ()
-'\" or
-'\" .BR env.SetOption (),
-'\" if conditions in a
-'\" .B SConscript
-'\" require overriding any default value.
-'\" Note, however, that a
-'\" value specified on the command line will
-'\" .I always
-'\" override a value set by any SConscript file.
-
-Any specified
-.B help=
-strings for the new option(s)
-will be displayed by the
-.B -H
-or
-.B -h
-options
-(the latter only if no other help text is
-specified in the SConscript files).
-The help text for the local options specified by
-.BR AddOption ()
-will appear below the SCons options themselves,
-under a separate
-.B "Local Options"
-heading.
-The options will appear in the help text
-in the order in which the
-.BR AddOption ()
-calls occur.
-
-Example:
-
-.ES
-AddOption('--prefix',
-          dest='prefix',
-          nargs=1, type='string',
-          action='store',
-          metavar='DIR',
-          help='installation prefix')
-env = Environment(PREFIX = GetOption('prefix'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AddPostAction( target ", " action )
-.TP
-.RI env.AddPostAction( target ", " action )
-Arranges for the specified
-.I action
-to be performed
-after the specified
-.I target
-has been built.
-The specified action(s) may be
-an Action object, or anything that
-can be converted into an Action object
-(see below).
-
-When multiple targets are supplied,
-the action may be called multiple times,
-once after each action that generates
-one or more targets in the list.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AddPreAction( target ", " action )
-.TP
-.RI env.AddPreAction( target ", " action )
-Arranges for the specified
-.I action
-to be performed
-before the specified
-.I target
-is built.
-The specified action(s) may be
-an Action object, or anything that
-can be converted into an Action object
-(see below).
-
-When multiple targets are specified,
-the action(s) may be called multiple times,
-once before each action that generates
-one or more targets in the list.
-
-Note that if any of the targets are built in multiple steps,
-the action will be invoked just
-before the "final" action that specifically
-generates the specified target(s).
-For example, when building an executable program
-from a specified source
-.B .c
-file via an intermediate object file:
-
-.ES
-foo = Program('foo.c')
-AddPreAction(foo, 'pre_action')
-.EE
-
-The specified
-.B pre_action
-would be executed before
-.B scons
-calls the link command that actually
-generates the executable program binary
-.BR foo ,
-not before compiling the
-.B foo.c
-file into an object file.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Alias( alias ", [" targets ", [" action ]])
-.TP
-.RI env.Alias( alias ", [" targets ", [" action ]])
-Creates one or more phony targets that
-expand to one or more other targets.
-An optional
-.I action
-(command)
-or list of actions
-can be specified that will be executed
-whenever the any of the alias targets are out-of-date.
-Returns the Node object representing the alias,
-which exists outside of any file system.
-This Node object, or the alias name,
-may be used as a dependency of any other target,
-including another alias.
-.B Alias
-can be called multiple times for the same
-alias to add additional targets to the alias,
-or additional actions to the list for this alias.
-
-Examples:
-
-.ES
-Alias('install')
-Alias('install', '/usr/bin')
-Alias(['install', 'install-lib'], '/usr/local/lib')
-
-env.Alias('install', ['/usr/local/bin', '/usr/local/lib'])
-env.Alias('install', ['/usr/local/man'])
-
-env.Alias('update', ['file1', 'file2'], "update_database $SOURCES")
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AllowSubstExceptions([ exception ", ...])"
-Specifies the exceptions that will be allowed
-when expanding construction variables.
-By default,
-any construction variable expansions that generate a
-.B NameError
-or
-.BR IndexError
-exception will expand to a
-.B ''
-(a null string) and not cause scons to fail.
-All exceptions not in the specified list
-will generate an error message
-and terminate processing.
-
-If
-.B AllowSubstExceptions
-is called multiple times,
-each call completely overwrites the previous list
-of allowed exceptions.
-
-Example:
-
-.ES
-# Requires that all construction variable names exist.
-# (You may wish to do this if you want to enforce strictly
-# that all construction variables must be defined before use.)
-AllowSubstExceptions()
-
-# Also allow a string containing a zero-division expansion
-# like '${1 / 0}' to evalute to ''.
-AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI AlwaysBuild( target ", ...)"
-.TP
-.RI env.AlwaysBuild( target ", ...)"
-Marks each given
-.I target
-so that it is always assumed to be out of date,
-and will always be rebuilt if needed.
-Note, however, that
-.BR AlwaysBuild ()
-does not add its target(s) to the default target list,
-so the targets will only be built
-if they are specified on the command line,
-or are a dependent of a target specified on the command line--but
-they will
-.I always
-be built if so specified.
-Multiple targets can be passed in to a single call to
-.BR AlwaysBuild ().
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Append( key = val ", [...])"
-Appends the specified keyword arguments
-to the end of construction variables in the environment.
-If the Environment does not have
-the specified construction variable,
-it is simply added to the environment.
-If the values of the construction variable
-and the keyword argument are the same type,
-then the two values will be simply added together.
-Otherwise, the construction variable
-and the value of the keyword argument
-are both coerced to lists,
-and the lists are added together.
-(See also the Prepend method, below.)
-
-Example:
-
-.ES
-env.Append(CCFLAGS = ' -g', FOO = ['foo.yyy'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.AppendENVPath( name ", " newpath ", [" envname ", " sep ", " delete_existing ])
-This appends new path elements to the given path in the
-specified external environment
-.RB ( ENV
-by default).
-This will only add
-any particular path once (leaving the last one it encounters and
-ignoring the rest, to preserve path order),
-and to help assure this,
-will normalize all paths (using
-.B os.path.normpath
-and
-.BR os.path.normcase ).
-This can also handle the
-case where the given old path variable is a list instead of a
-string, in which case a list will be returned instead of a string.
-
-If 
-.I delete_existing
-is 0, then adding a path that already exists
-will not move it to the end; it will stay where it is in the list.
-
-Example:
-
-.ES
-print 'before:',env['ENV']['INCLUDE']
-include_path = '/foo/bar:/foo'
-env.AppendENVPath('INCLUDE', include_path)
-print 'after:',env['ENV']['INCLUDE']
-
-yields:
-before: /foo:/biz
-after: /biz:/foo/bar:/foo
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.AppendUnique( key = val ", [...], delete_existing=0)"
-Appends the specified keyword arguments
-to the end of construction variables in the environment.
-If the Environment does not have
-the specified construction variable,
-it is simply added to the environment.
-If the construction variable being appended to is a list,
-then any value(s) that already exist in the
-construction variable will
-.I not
-be added again to the list.
-However, if delete_existing is 1, 
-existing matching values are removed first, so
-existing values in the arg list move to the end of the list.
-
-Example:
-
-.ES
-env.AppendUnique(CCFLAGS = '-g', FOO = ['foo.yyy'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-env.BitKeeper()
-A factory function that
-returns a Builder object
-to be used to fetch source files
-using BitKeeper.
-The returned Builder
-is intended to be passed to the
-.B SourceCode
-function.
-
-This function is deprecated.  For details, see the entry for the
-.B SourceCode
-function.
-
-Example:
-
-.ES
-env.SourceCode('.', env.BitKeeper())
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI BuildDir( build_dir ", " src_dir ", [" duplicate ])
-.TP
-.RI env.BuildDir( build_dir ", " src_dir ", [" duplicate ])
-Deprecated synonyms for
-.BR VariantDir ()
-and
-.BR env.VariantDir ().
-The
-.I build_dir
-argument becomes the
-.I variant_dir
-argument of
-.BR VariantDir ()
-or
-.BR env.VariantDir ().
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Builder( action ", [" arguments ])
-.TP
-.RI env.Builder( action ", [" arguments ])
-Creates a Builder object for
-the specified
-.IR action .
-See the section "Builder Objects,"
-below, for a complete explanation of the arguments and behavior.
-
-Note that the
-.BR env.Builder ()
-form of the invocation will expand
-construction variables in any arguments strings,
-including the
-.I action
-argument,
-at the time it is called
-using the construction variables in the
-.B env
-construction environment through which
-.BR env.Builder ()
-was called.
-The
-.BR Builder ()
-form delays all variable expansion
-until after the Builder object is actually called.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI CacheDir( cache_dir )
-.TP
-.RI env.CacheDir( cache_dir )
-Specifies that
-.B scons
-will maintain a cache of derived files in
-.I cache_dir .
-The derived files in the cache will be shared
-among all the builds using the same
-.BR CacheDir ()
-call.
-Specifying a
-.I cache_dir
-of
-.B None
-disables derived file caching.
-
-Calling
-.BR env.CacheDir ()
-will only affect targets built
-through the specified construction environment.
-Calling
-.BR CacheDir ()
-sets a global default
-that will be used by all targets built
-through construction environments
-that do
-.I not
-have an
-.BR env.CacheDir ()
-specified.
-
-When a
-.BR CacheDir ()
-is being used and
-.B scons
-finds a derived file that needs to be rebuilt,
-it will first look in the cache to see if a
-derived file has already been built
-from identical input files and an identical build action
-(as incorporated into the MD5 build signature).
-If so,
-.B scons
-will retrieve the file from the cache.
-If the derived file is not present in the cache,
-.B scons
-will rebuild it and
-then place a copy of the built file in the cache
-(identified by its MD5 build signature),
-so that it may be retrieved by other
-builds that need to build the same derived file
-from identical inputs.
-
-Use of a specified
-.BR CacheDir()
-may be disabled for any invocation
-by using the
-.B --cache-disable
-option.
-
-If the
-.B --cache-force
-option is used,
-.B scons
-will place a copy of
-.I all
-derived files in the cache,
-even if they already existed
-and were not built by this invocation.
-This is useful to populate a cache
-the first time
-.BR CacheDir ()
-is added to a build,
-or after using the
-.B --cache-disable
-option.
-
-When using
-.BR CacheDir (),
-.B scons
-will report,
-"Retrieved `file' from cache,"
-unless the
-.B --cache-show
-option is being used.
-When the
-.B --cache-show
-option is used,
-.B scons
-will print the action that
-.I would
-have been used to build the file,
-without any indication that
-the file was actually retrieved from the cache.
-This is useful to generate build logs
-that are equivalent regardless of whether
-a given derived file has been built in-place
-or retrieved from the cache.
-
-The
-.BR NoCache ()
-method can be used to disable caching of specific files.  This can be
-useful if inputs and/or outputs of some tool are impossible to
-predict or prohibitively large.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Clean( targets ", " files_or_dirs )
-.TP
-.RI env.Clean( targets ", " files_or_dirs )
-This specifies a list of files or directories which should be removed
-whenever the targets are specified with the
-.B -c
-command line option.
-The specified targets may be a list
-or an individual target.
-Multiple calls to
-.BR Clean ()
-are legal,
-and create new targets or add files and directories to the
-clean list for the specified targets.
-
-Multiple files or directories should be specified
-either as separate arguments to the
-.BR Clean ()
-method, or as a list.
-.BR Clean ()
-will also accept the return value of any of the construction environment
-Builder methods.
-Examples:
-
-The related
-.BR NoClean ()
-function overrides calling
-.BR Clean ()
-for the same target,
-and any targets passed to both functions will
-.I not
-be removed by the
-.B -c
-option.
-
-Examples:
-
-.ES
-Clean('foo', ['bar', 'baz'])
-Clean('dist', env.Program('hello', 'hello.c'))
-Clean(['foo', 'bar'], 'something_else_to_clean')
-.EE
-
-.IP
-In this example,
-installing the project creates a subdirectory for the documentation.
-This statement causes the subdirectory to be removed
-if the project is deinstalled.
-.ES
-Clean(docdir, os.path.join(docdir, projectname))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Command( target ", " source ", " action ", [" key = val ", ...])"
-.TP
-.RI env.Command( target ", " source ", " action ", [" key = val ", ...])"
-Executes a specific action
-(or list of actions)
-to build a target file or files.
-This is more convenient
-than defining a separate Builder object
-for a single special-case build.
-
-As a special case, the
-.B source_scanner
-keyword argument can
-be used to specify
-a Scanner object
-that will be used to scan the sources.
-(The global
-.B DirScanner
-object can be used
-if any of the sources will be directories
-that must be scanned on-disk for
-changes to files that aren't
-already specified in other Builder of function calls.)
-
-Any other keyword arguments specified override any
-same-named existing construction variables.
-
-An action can be an external command,
-specified as a string,
-or a callable Python object;
-see "Action Objects," below,
-for more complete information.
-Also note that a string specifying an external command
-may be preceded by an
-.B @
-(at-sign)
-to suppress printing the command in question,
-or by a
-.B \-
-(hyphen)
-to ignore the exit status of the external command.
-
-Examples:
-
-.ES
-env.Command('foo.out', 'foo.in',
-            "$FOO_BUILD < $SOURCES > $TARGET")
-
-env.Command('bar.out', 'bar.in',
-            ["rm -f $TARGET",
-             "$BAR_BUILD < $SOURCES > $TARGET"],
-            ENV = {'PATH' : '/usr/local/bin/'})
-
-def rename(env, target, source):
-    import os
-    os.rename('.tmp', str(target[0]))
-
-env.Command('baz.out', 'baz.in',
-            ["$BAZ_BUILD < $SOURCES > .tmp",
-	     rename ])
-.EE
-
-.IP
-Note that the
-.BR Command ()
-function will usually assume, by default,
-that the specified targets and/or sources are Files,
-if no other part of the configuration
-identifies what type of entry it is.
-If necessary, you can explicitly specify
-that targets or source nodes should
-be treated as directoriese
-by using the
-.BR Dir ()
-or
-.BR env.Dir ()
-functions.
-
-Examples:
-
-.ES
-env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET')
-
-env['DISTDIR'] = 'destination/directory'
-env.Command(env.Dir('$DISTDIR')), None, make_distdir)
-.EE
-
-.IP
-(Also note that SCons will usually
-automatically create any directory necessary to hold a target file,
-so you normally don't need to create directories by hand.)
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Configure( env ", [" custom_tests ", " conf_dir ", " log_file ", " config_h ])
-.TP
-.RI env.Configure([ custom_tests ", " conf_dir ", " log_file ", " config_h ])
-Creates a Configure object for integrated
-functionality similar to GNU autoconf.
-See the section "Configure Contexts,"
-below, for a complete explanation of the arguments and behavior.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Clone([ key = val ", ...])"
-Return a separate copy of a construction environment.
-If there are any keyword arguments specified,
-they are added to the returned copy,
-overwriting any existing values
-for the keywords.
-
-Example:
-
-.ES
-env2 = env.Clone()
-env3 = env.Clone(CCFLAGS = '-g')
-.EE
-.IP
-Additionally, a list of tools and a toolpath may be specified, as in
-the Environment constructor:
-
-.ES
-def MyTool(env): env['FOO'] = 'bar'
-env4 = env.Clone(tools = ['msvc', MyTool])
-.EE
-
-The
-.I parse_flags
-keyword argument is also recognized:
-
-.ES
-# create an environment for compiling programs that use wxWidgets
-wx_env = env.Clone(parse_flags = '!wx-config --cflags --cxxflags')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Copy([ key = val ", ...])"
-A now-deprecated synonym for
-.BR env.Clone() .
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.CVS( repository ", " module )
-A factory function that
-returns a Builder object
-to be used to fetch source files
-from the specified
-CVS
-.IR repository .
-The returned Builder
-is intended to be passed to the
-.B SourceCode
-function.
-
-The optional specified
-.I module
-will be added to the beginning
-of all repository path names;
-this can be used, in essence,
-to strip initial directory names
-from the repository path names,
-so that you only have to
-replicate part of the repository
-directory hierarchy in your
-local build directory.
-
-This function is deprecated.  For details, see the entry for the
-.B SourceCode
-function.
-
-Examples:
-
-.ES
-# Will fetch foo/bar/src.c
-# from /usr/local/CVSROOT/foo/bar/src.c.
-env.SourceCode('.', env.CVS('/usr/local/CVSROOT'))
-
-# Will fetch bar/src.c
-# from /usr/local/CVSROOT/foo/bar/src.c.
-env.SourceCode('.', env.CVS('/usr/local/CVSROOT', 'foo'))
-
-# Will fetch src.c
-# from /usr/local/CVSROOT/foo/bar/src.c.
-env.SourceCode('.', env.CVS('/usr/local/CVSROOT', 'foo/bar'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Decider( function )
-.TP
-.RI env.Decider( function )
-Specifies that all up-to-date decisions for
-targets built through this construction environment
-will be handled by the specified
-.IR function .
-The
-.I function
-can be one of the following strings
-that specify the type of decision function
-to be performed:
-
-.RS 10
-.HP 6
-.B timestamp-newer
-Specifies that a target shall be considered out of date and rebuilt
-if the dependency's timestamp is newer than the target file's timestamp.
-This is the behavior of the classic Make utility,
-and
-.B make
-can be used a synonym for
-.BR timestamp-newer .
-
-.HP 6
-.B timestamp-match
-Specifies that a target shall be considered out of date and rebuilt
-if the dependency's timestamp is different than the
-timestamp recorded the last time the target was built.
-This provides behavior very similar to the classic Make utility
-(in particular, files are not opened up so that their
-contents can be checksummed)
-except that the target will also be rebuilt if a
-dependency file has been restored to a version with an
-.I earlier
-timestamp, such as can happen when restoring files from backup archives.
-
-.HP 6
-.B MD5
-Specifies that a target shall be considered out of date and rebuilt
-if the dependency's content has changed sine the last time
-the target was built,
-as determined be performing an MD5 checksum
-on the dependency's contents
-and comparing it to the checksum recorded the
-last time the target was built.
-.B content
-can be used as a synonym for
-.BR MD5 .
-
-.HP 6
-.B MD5-timestamp
-Specifies that a target shall be considered out of date and rebuilt
-if the dependency's content has changed sine the last time
-the target was built,
-except that dependencies with a timestamp that matches
-the last time the target was rebuilt will be
-assumed to be up-to-date and
-.I not
-rebuilt.
-This provides behavior very similar
-to the
-.B MD5
-behavior of always checksumming file contents,
-with an optimization of not checking
-the contents of files whose timestamps haven't changed.
-The drawback is that SCons will
-.I not
-detect if a file's content has changed
-but its timestamp is the same,
-as might happen in an automated script
-that runs a build,
-updates a file,
-and runs the build again,
-all within a single second.
-.RE
-
-.IP
-Examples:
-
-.ES
-# Use exact timestamp matches by default.
-Decider('timestamp-match')
-
-# Use MD5 content signatures for any targets built
-# with the attached construction environment.
-env.Decider('content')
-.EE
-
-.IP
-In addition to the above already-available functions,
-the
-.I function
-argument may be an actual Python function
-that takes the following three arguments:
-
-.RS 10
-.IP dependency
-The Node (file) which
-should cause the
-.I target
-to be rebuilt
-if it has "changed" since the last tme
-.I target was built.
-
-.IP target
-The Node (file) being built.
-In the normal case,
-this is what should get rebuilt
-if the
-.I dependency
-has "changed."
-
-.IP prev_ni
-Stored information about the state of the
-.I dependency
-the last time the
-.I target
-was built.
-This can be consulted to match various
-file characteristics
-such as the timestamp,
-size, or content signature.
-.RE
-
-.IP
-The
-.I function
-should return a
-.B True
-(non-zero)
-value if the
-.I dependency
-has "changed" since the last time
-the
-.I target
-was built
-(indicating that the target
-.I should
-be rebuilt),
-and
-.B False
-(zero)
-otherwise
-(indicating that the target should
-.I not
-be rebuilt).
-Note that the decision can be made
-using whatever criteria are appopriate.
-Ignoring some or all of the function arguments
-is perfectly normal.
-
-Example:
-
-.ES
-def my_decider(dependency, target, prev_ni):
-    return not os.path.exists(str(target))
-
-env.Decider(my_decider)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Default( targets )
-.TP
-.RI env.Default( targets )
-This specifies a list of default targets,
-which will be built by
-.B scons
-if no explicit targets are given on the command line.
-Multiple calls to
-.BR Default ()
-are legal,
-and add to the list of default targets.
-
-Multiple targets should be specified as
-separate arguments to the
-.BR Default ()
-method, or as a list.
-.BR Default ()
-will also accept the Node returned by any
-of a construction environment's
-builder methods.
-
-Examples:
-
-.ES
-Default('foo', 'bar', 'baz')
-env.Default(['a', 'b', 'c'])
-hello = env.Program('hello', 'hello.c')
-env.Default(hello)
-.EE
-.IP
-An argument to
-.BR Default ()
-of
-.B None
-will clear all default targets.
-Later calls to
-.BR Default ()
-will add to the (now empty) default-target list
-like normal.
-
-The current list of targets added using the
-.BR Default ()
-function or method is available in the
-.B DEFAULT_TARGETS
-list;
-see below.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI DefaultEnvironment([ args ])
-Creates and returns a default construction environment object.
-This construction environment is used internally by SCons
-in order to execute many of the global functions in this list,
-and to fetch source files transparently
-from source code management systems.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Depends( target ", " dependency )
-.TP
-.RI env.Depends( target ", " dependency )
-Specifies an explicit dependency;
-the
-.I target
-will be rebuilt
-whenever the
-.I dependency
-has changed.
-Both the specified
-.I target
-and
-.I dependency
-can be a string
-(usually the path name of a file or directory)
-or Node objects,
-or a list of strings or Node objects
-(such as returned by a Builder call).
-This should only be necessary
-for cases where the dependency
-is not caught by a Scanner
-for the file.
-
-Example:
-
-.ES
-env.Depends('foo', 'other-input-file-for-foo')
-
-mylib = env.Library('mylib.c')
-installed_lib = env.Install('lib', mylib)
-bar = env.Program('bar.c')
-
-# Arrange for the library to be copied into the installation
-# directory before trying to build the "bar" program.
-# (Note that this is for example only.  A "real" library
-# dependency would normally be configured through the $LIBS
-# and $LIBPATH variables, not using an env.Depends() call.)
-
-env.Depends(bar, installed_lib)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Dictionary([ vars ])
-Returns a dictionary object
-containing copies of all of the
-construction variables in the environment.
-If there are any variable names specified,
-only the specified construction
-variables are returned in the dictionary.
-
-Example:
-
-.ES
-dict = env.Dictionary()
-cc_dict = env.Dictionary('CC', 'CCFLAGS', 'CCCOM')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Dir( name ", [" directory ])
-.TP
-.RI env.Dir( name ", [" directory ])
-This returns a Directory Node,
-an object that represents the specified directory
-.IR name .
-.I name
-can be a relative or absolute path.
-.I directory
-is an optional directory that will be used as the parent directory.
-If no
-.I directory
-is specified, the current script's directory is used as the parent.
-
-If
-.I name
-is a list, SCons returns a list of Dir nodes.
-Construction variables are expanded in
-.IR name .
-
-Directory Nodes can be used anywhere you
-would supply a string as a directory name
-to a Builder method or function.
-Directory Nodes have attributes and methods
-that are useful in many situations;
-see "File and Directory Nodes," below.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Dump([ key ])
-Returns a pretty printable representation of the environment.
-.IR key ,
-if not
-.IR None ,
-should be a string containing the name of the variable of interest.
-
-This SConstruct:
-.ES
-env=Environment()
-print env.Dump('CCCOM')
-.EE
-.IP
-will print:
-.ES
-\&'$CC -c -o $TARGET $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES'
-.EE
-
-.ES
-env=Environment()
-print env.Dump()
-.EE
-.IP
-will print:
-.ES
-{ 'AR': 'ar',
-  'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET',
-  'ARFLAGS': ['r'],
-  'AS': 'as',
-  'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES',
-  'ASFLAGS': [],
-  ...
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI EnsurePythonVersion( major ", " minor )
-.TP
-.RI env.EnsurePythonVersion( major ", " minor )
-Ensure that the Python version is at least
-.IR major . minor .
-This function will
-print out an error message and exit SCons with a non-zero exit code if the
-actual Python version is not late enough.
-
-Example:
-
-.ES
-EnsurePythonVersion(2,2)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI EnsureSConsVersion( major ", " minor ", [" revision ])
-.TP
-.RI env.EnsureSConsVersion( major ", " minor ", [" revision ])
-Ensure that the SCons version is at least
-.IR major.minor ,
-or
-.IR major.minor.revision .
-if
-.I revision
-is specified.
-This function will
-print out an error message and exit SCons with a non-zero exit code if the
-actual SCons version is not late enough.
-
-Examples:
-
-.ES
-EnsureSConsVersion(0,14)
-
-EnsureSConsVersion(0,96,90)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Environment([ key = value ", ...])"
-.TP
-.RI env.Environment([ key = value ", ...])"
-Return a new construction environment
-initialized with the specified
-.IR key = value
-pairs.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Execute( action ", [" strfunction ", " varlist ])
-.TP
-.RI env.Execute( action ", [" strfunction ", " varlist ])
-Executes an Action object.
-The specified
-.IR action
-may be an Action object
-(see the section "Action Objects,"
-below, for a complete explanation of the arguments and behavior),
-or it may be a command-line string,
-list of commands,
-or executable Python function,
-each of which will be converted
-into an Action object
-and then executed.
-The exit value of the command
-or return value of the Python function
-will be returned.
-
-Note that
-.B scons
-will print an error message if the executed
-.I action
-fails--that is,
-exits with or returns a non-zero value.
-.B scons
-will
-.I not ,
-however,
-automatically terminate the build
-if the specified
-.I action
-fails.
-If you want the build to stop in response to a failed
-.BR Execute ()
-call,
-you must explicitly check for a non-zero return value:
-
-.ES
-Execute(Copy('file.out', 'file.in'))
-
-if Execute("mkdir sub/dir/ectory"):
-    # The mkdir failed, don't try to build.
-    Exit(1)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Exit([ value ])
-.TP
-.RI env.Exit([ value ])
-This tells
-.B scons
-to exit immediately
-with the specified
-.IR value .
-A default exit value of
-.B 0
-(zero)
-is used if no value is specified.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Export( vars )
-.TP
-.RI env.Export( vars )
-This tells
-.B scons
-to export a list of variables from the current
-SConscript file to all other SConscript files.
-The exported variables are kept in a global collection,
-so subsequent calls to
-.BR Export ()
-will over-write previous exports that have the same name.
-Multiple variable names can be passed to
-.BR Export ()
-as separate arguments or as a list.
-Keyword arguments can be used to provide names and their values.
-A dictionary can be used to map variables to a different name when exported.
-Both local variables and global variables can be exported.
-
-Examples:
-
-.ES
-env = Environment()
-# Make env available for all SConscript files to Import().
-Export("env")
-
-package = 'my_name'
-# Make env and package available for all SConscript files:.
-Export("env", "package")
-
-# Make env and package available for all SConscript files:
-Export(["env", "package"])
-
-# Make env available using the name debug:
-Export(debug = env)
-
-# Make env available using the name debug:
-Export({"debug":env})
-.EE
-
-.IP
-Note that the
-.BR SConscript ()
-function supports an
-.I exports
-argument that makes it easier to to export a variable or
-set of variables to a single SConscript file.
-See the description of the
-.BR SConscript ()
-function, below.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI File( name ", [" directory ])
-.TP
-.RI env.File( name ", [" directory ])
-This returns a
-File Node,
-an object that represents the specified file
-.IR name .
-.I name
-can be a relative or absolute path.
-.I directory
-is an optional directory that will be used as the parent directory.
-
-If
-.I name
-is a list, SCons returns a list of File nodes.
-Construction variables are expanded in
-.IR name .
-
-File Nodes can be used anywhere you
-would supply a string as a file name
-to a Builder method or function.
-File Nodes have attributes and methods
-that are useful in many situations;
-see "File and Directory Nodes," below.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI FindFile( file ", " dirs )
-.TP
-.RI env.FindFile( file ", " dirs )
-Search for
-.I file
-in the path specified by
-.IR dirs .
-.I dirs
-may be a list of directory names or a single directory name.
-In addition to searching for files that exist in the filesystem,
-this function also searches for derived files
-that have not yet been built.
-
-Example:
-
-.ES
-foo = env.FindFile('foo', ['dir1', 'dir2'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI FindInstalledFiles( )
-.TP
-.RI env.FindInstalledFiles( )
-Returns the list of targets set up by the
-.B Install()
-or
-.B InstallAs()
-builders.
-
-This function serves as a convenient method to select the contents of
-a binary package.
-
-Example:
-
-.ES
-Install( '/bin', [ 'executable_a', 'executable_b' ] )
-
-# will return the file node list
-# [ '/bin/executable_a', '/bin/executable_b' ]
-FindInstalledFiles()
-
-Install( '/lib', [ 'some_library' ] )
-
-# will return the file node list
-# [ '/bin/executable_a', '/bin/executable_b', '/lib/some_library' ]
-FindInstalledFiles()
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI FindSourceFiles( node = '"."' )
-.TP
-.RI env.FindSourceFiles( node = '"."' )
-
-Returns the list of nodes which serve as the source of the built files.
-It does so by inspecting the dependency tree starting at the optional
-argument
-.B node
-which defaults to the '"."'-node. It will then return all leaves of
-.B node.
-These are all children which have no further children.
-
-This function is a convenient method to select the contents of a Source
-Package.
-
-Example:
-
-.ES
-Program( 'src/main_a.c' )
-Program( 'src/main_b.c' )
-Program( 'main_c.c' )
-
-# returns ['main_c.c', 'src/main_a.c', 'SConstruct', 'src/main_b.c']
-FindSourceFiles()
-
-# returns ['src/main_b.c', 'src/main_a.c' ]
-FindSourceFiles( 'src' )
-.EE
-
-.IP
-As you can see build support files (SConstruct in the above example)
-will also be returned by this function.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI FindPathDirs( variable )
-Returns a function
-(actually a callable Python object)
-intended to be used as the
-.B path_function
-of a Scanner object.
-The returned object will look up the specified
-.I variable
-in a construction environment
-and treat the construction variable's value as a list of
-directory paths that should be searched
-(like
-.BR CPPPATH ,
-.BR LIBPATH ,
-etc.).
-
-Note that use of
-.BR FindPathDirs ()
-is generally preferable to
-writing your own
-.B path_function
-for the following reasons:
-1) The returned list will contain all appropriate directories
-found in source trees
-(when
-.BR VariantDir ()
-is used)
-or in code repositories
-(when
-.BR Repository ()
-or the
-.B \-Y
-option are used).
-2) scons will identify expansions of
-.I variable
-that evaluate to the same list of directories as,
-in fact, the same list,
-and avoid re-scanning the directories for files,
-when possible.
-
-Example:
-
-.ES
-def my_scan(node, env, path, arg):
-    # Code to scan file contents goes here...
-    return include_files
-
-scanner = Scanner(name = 'myscanner',
-                  function = my_scan,
-                  path_function = FindPathDirs('MYPATH'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Flatten( sequence )
-.TP
-.RI env.Flatten( sequence )
-Takes a sequence (that is, a Python list or tuple)
-that may contain nested sequences
-and returns a flattened list containing
-all of the individual elements in any sequence.
-This can be helpful for collecting
-the lists returned by calls to Builders;
-other Builders will automatically
-flatten lists specified as input,
-but direct Python manipulation of
-these lists does not.
-
-Examples:
-
-.ES
-foo = Object('foo.c')
-bar = Object('bar.c')
-
-# Because `foo' and `bar' are lists returned by the Object() Builder,
-# `objects' will be a list containing nested lists:
-objects = ['f1.o', foo, 'f2.o', bar, 'f3.o']
-
-# Passing such a list to another Builder is all right because
-# the Builder will flatten the list automatically:
-Program(source = objects)
-
-# If you need to manipulate the list directly using Python, you need to
-# call Flatten() yourself, or otherwise handle nested lists:
-for object in Flatten(objects):
-    print str(object)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI GetBuildFailures()
-Returns a list of exceptions for the
-actions that failed while
-attempting to build targets.
-Each element in the returned list is a
-.B BuildError
-object
-with the following attributes
-that record various aspects
-of the build failure:
-
-.B .node
-The node that was being built
-when the build failure occurred.
-
-.B .status
-The numeric exit status
-returned by the command or Python function
-that failed when trying to build the
-specified Node.
-
-.B .errstr
-The SCons error string
-describing the build failure.
-(This is often a generic
-message like "Error 2"
-to indicate that an executed
-command exited with a status of 2.)
-
-.B .filename
-The name of the file or
-directory that actually caused the failure.
-This may be different from the
-.B .node
-attribute.
-For example,
-if an attempt to build a target named
-.B sub/dir/target
-fails because the
-.B sub/dir
-directory could not be created,
-then the
-.B .node
-attribute will be
-.B sub/dir/target
-but the
-.B .filename
-attribute will be
-.BR sub/dir .
-
-.B .executor
-The SCons Executor object
-for the target Node
-being built.
-This can be used to retrieve
-the construction environment used
-for the failed action.
-
-.B .action
-The actual SCons Action object that failed.
-This will be one specific action
-out of the possible list of
-actions that would have been
-executed to build the target.
-
-.B .command
-The actual expanded command that was executed and failed,
-after expansion of
-.BR $TARGET ,
-.BR $SOURCE ,
-and other construction variables.
-
-Note that the
-.BR GetBuildFailures ()
-function
-will always return an empty list
-until any build failure has occurred,
-which means that
-.BR GetBuildFailures ()
-will always return an empty list
-while the
-.B SConscript
-files are being read.
-Its primary intended use is
-for functions that will be
-executed before SCons exits
-by passing them to the
-standard Python
-.BR atexit.register ()
-function.
-Example:
-
-.ES
-import atexit
-
-def print_build_failures():
-    from SCons.Script import GetBuildFailures
-    for bf in GetBuildFailures():
-        print "%s failed: %s" % (bf.node, bf.errstr)
-
-atexit.register(print_build_failures)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI GetBuildPath( file ", [" ... ])
-.TP
-.RI env.GetBuildPath( file ", [" ... ])
-Returns the
-.B scons
-path name (or names) for the specified
-.I file
-(or files).
-The specified
-.I file
-or files
-may be
-.B scons
-Nodes or strings representing path names.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI GetLaunchDir()
-.TP
-.RI env.GetLaunchDir()
-Returns the absolute path name of the directory from which
-.B scons
-was initially invoked.
-This can be useful when using the
-.BR \-u ,
-.BR \-U
-or
-.BR \-D
-options, which internally
-change to the directory in which the
-.B SConstruct
-file is found.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI GetOption( name )
-.TP
-.RI env.GetOption( name )
-This function provides a way to query the value of
-SCons options set on scons command line
-(or set using the
-.IR SetOption ()
-function).
-The options supported are:
-
-.RS 10
-.TP 6
-.B cache_debug
-which corresponds to --cache-debug;
-.TP 6
-.B cache_disable
-which corresponds to --cache-disable;
-.TP 6
-.B cache_force
-which corresponds to --cache-force;
-.TP 6
-.B cache_show
-which corresponds to --cache-show;
-.TP 6
-.B clean
-which corresponds to -c, --clean and --remove;
-.TP 6
-.B config
-which corresponds to --config;
-.TP 6
-.B directory
-which corresponds to -C and --directory;
-.TP 6
-.B diskcheck
-which corresponds to --diskcheck
-.TP 6
-.B duplicate
-which corresponds to --duplicate;
-.TP 6
-.B file
-which corresponds to -f, --file, --makefile and --sconstruct;
-.TP 6
-.B help
-which corresponds to -h and --help;
-.TP 6
-.B ignore_errors
-which corresponds to --ignore-errors;
-.TP 6
-.B implicit_cache
-which corresponds to --implicit-cache;
-.TP 6
-.B implicit_deps_changed
-which corresponds to --implicit-deps-changed;
-.TP 6
-.B implicit_deps_unchanged
-which corresponds to --implicit-deps-unchanged;
-.TP 6
-.B interactive
-which corresponds to --interact and --interactive;
-.TP 6
-.B keep_going
-which corresponds to -k and --keep-going;
-.TP 6
-.B max_drift
-which corresponds to --max-drift;
-.TP 6
-.B no_exec
-which corresponds to -n, --no-exec, --just-print, --dry-run and --recon;
-.TP 6
-.B no_site_dir
-which corresponds to --no-site-dir;
-.TP 6
-.B num_jobs
-which corresponds to -j and --jobs;
-.TP 6
-.B profile_file
-which corresponds to --profile;
-.TP 6
-.B question
-which corresponds to -q and --question;
-.TP 6
-.B random
-which corresponds to --random;
-.TP 6
-.B repository
-which corresponds to -Y, --repository and --srcdir;
-.TP 6
-.B silent
-which corresponds to -s, --silent and --quiet;
-.TP 6
-.B site_dir
-which corresponds to --site-dir;
-.TP 6
-.B stack_size
-which corresponds to --stack-size;
-.TP 6
-.B taskmastertrace_file
-which corresponds to --taskmastertrace; and
-.TP 6
-.B warn
-which corresponds to --warn and --warning.
-.RE
-
-.IP
-See the documentation for the
-corresponding command line object for information about each specific
-option.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Glob( pattern ", [" ondisk ", " source ", " strings ])
-.TP
-.RI env.Glob( pattern ", [" ondisk ", " source ", " strings ])
-Returns Nodes (or strings) that match the specified
-.IR pattern ,
-relative to the directory of the current
-.B SConscript
-file.
-The
-.BR env.Glob ()
-form performs string substition on
-.I pattern
-and returns whatever matches
-the resulting expanded pattern.
-
-The specified
-.I pattern
-uses Unix shell style metacharacters for matching:
-
-.ES
-  *       matches everything
-  ?       matches any single character
-  [seq]   matches any character in seq
-  [!seq]  matches any char not in seq
-.EE
-
-.IP
-If the first character of a filename is a dot,
-it must be matched explicitly.
-Character matches do
-.I not
-span directory separators.
-
-The
-.BR Glob ()
-knows about
-repositories
-(see the
-.BR Repository ()
-function)
-and source directories
-(see the
-.BR VariantDir ()
-function)
-and
-returns a Node (or string, if so configured)
-in the local (SConscript) directory
-if matching Node is found
-anywhere in a corresponding
-repository or source directory.
-
-The
-.B ondisk
-argument may be set to
-.B False
-(or any other non-true value)
-to disable the search for matches on disk,
-thereby only returning matches among
-already-configured File or Dir Nodes.
-The default behavior is to
-return corresponding Nodes
-for any on-disk matches found.
-
-The
-.B source
-argument may be set to
-.B True
-(or any equivalent value)
-to specify that,
-when the local directory is a
-.BR VariantDir (),
-the returned Nodes should be from the
-corresponding source directory,
-not the local directory.
-
-The
-.B strings
-argument may be set to
-.B True
-(or any equivalent value)
-to have the
-.BR Glob ()
-function return strings, not Nodes,
-that represent the matched files or directories.
-The returned strings will be relative to
-the local (SConscript) directory.
-(Note that This may make it easier to perform
-arbitrary manipulation of file names,
-but if the returned strings are
-passed to a different
-.B SConscript
-file,
-any Node translation will be relative
-to the other
-.B SConscript
-directory,
-not the original
-.B SConscript
-directory.)
-
-Examples:
-
-.ES
-Program('foo', Glob('*.c'))
-Zip('/tmp/everything', Glob('.??*') + Glob('*'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-'\".TP
-'\".RI GlobalBuilders( flag )
-'\"When
-'\".B flag
-'\"is non-zero,
-'\"adds the names of the default builders
-'\"(Program, Library, etc.)
-'\"to the global name space
-'\"so they can be called without an explicit construction environment.
-'\"(This is the default.)
-'\"When
-'\".B
-'\"flag is zero,
-'\"the names of the default builders are removed
-'\"from the global name space
-'\"so that an explicit construction environment is required
-'\"to call all builders.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Help( text )
-.TP
-.RI env.Help( text )
-This specifies help text to be printed if the
-.B -h
-argument is given to
-.BR scons .
-If
-.BR Help
-is called multiple times, the text is appended together in the order
-that
-.BR Help
-is called.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Ignore( target ", " dependency )
-.TP
-.RI env.Ignore( target ", " dependency )
-The specified dependency file(s)
-will be ignored when deciding if
-the target file(s) need to be rebuilt.
-
-You can also use
-.BR Ignore()
-to remove a target from the default build.
-In order to do this you must specify the directory the target will
-be built in as the target, and the file you want to skip building
-as the dependency.
-
-Note that this will only remove the dependencies listed from 
-the files built by default.  It will still be built if that 
-dependency is needed by another object being built. 
-See the third and forth examples below.
-
-Examples:
-
-.ES
-env.Ignore('foo', 'foo.c')
-env.Ignore('bar', ['bar1.h', 'bar2.h'])
-env.Ignore('.','foobar.obj')
-env.Ignore('bar','bar/foobar.obj')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Import( vars )
-.TP
-.RI env.Import( vars )
-This tells
-.B scons
-to import a list of variables into the current SConscript file. This
-will import variables that were exported with
-.BR Export ()
-or in the
-.I exports
-argument to
-.BR SConscript ().
-Variables exported by
-.BR SConscript ()
-have precedence.
-Multiple variable names can be passed to
-.BR Import ()
-as separate arguments or as a list. The variable "*" can be used
-to import all variables.
-
-Examples:
-
-.ES
-Import("env")
-Import("env", "variable")
-Import(["env", "variable"])
-Import("*")
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Literal( string )
-.TP
-.RI env.Literal( string )
-The specified
-.I string
-will be preserved as-is
-and not have construction variables expanded.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Local( targets )
-.TP
-.RI env.Local( targets )
-The specified
-.I targets
-will have copies made in the local tree,
-even if an already up-to-date copy
-exists in a repository.
-Returns a list of the target Node or Nodes.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-'\" .TP
-'\" .RI env.MergeShellPaths( arg ", [" prepend ])
-'\" Merges the elements of the specified
-'\" .IR arg ,
-'\" which must be a dictionary, to the construction
-'\" environment's copy of the shell environment
-'\" in env['ENV'].
-'\" (This is the environment which is passed
-'\" to subshells spawned by SCons.)
-'\" Note that
-'\" .I arg
-'\" must be a single value,
-'\" so multiple strings must
-'\" be passed in as a list,
-'\" not as separate arguments to
-'\" .BR env.MergeShellPaths ().
+'\" BEGIN GENERATED FUNCTION DESCRIPTIONS
 '\"
-'\" New values are prepended to the environment variable by default,
-'\" unless prepend=0 is specified.  
-'\" Duplicate values are always eliminated, 
-'\" since this function calls
-'\" .B AppendENVPath
-'\" or
-'\" .B PrependENVPath
-'\" depending on the
-'\" .I prepend
-'\" argument.  See those functions for more details.
-'\"
-'\" Examples:
-'\"
-'\" .ES
-'\" # Prepend a path to the shell PATH.
-'\" env.MergeShellPaths({'PATH':'/usr/local/bin'} )
-'\" # Append two dirs to the shell INCLUDE.
-'\" env.MergeShellPaths({'INCLUDE':['c:/inc1', 'c:/inc2']}, prepend=0 )
+'\" The descriptions below of the various SCons functions are generated
+'\" from the .xml files that live next to the various Python modules in
+'\" the build enginer library.  If you're reading this [gnt]roff file
+'\" with an eye towards patching this man page, you can still submit
+'\" a diff against this text, but it will have to be translated to a
+'\" diff against the underlying .xml file before the patch is actually
+'\" accepted.  If you do that yourself, it will make it easier to
+'\" integrate the patch.
 '\"
-'\".EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.MergeFlags( arg ", [" unique ])
-Merges the specified
-.I arg
-values to the construction environment's construction variables.
-If the
-.I arg
-argument is not a dictionary,
-it is converted to one by calling
-.B env.ParseFlags()
-on the argument
-before the values are merged.
-Note that
-.I arg
-must be a single value,
-so multiple strings must
-be passed in as a list,
-not as separate arguments to
-.BR env.MergeFlags ().
-
-By default,
-duplicate values are eliminated;
-you can, however, specify
-.B unique=0
-to allow duplicate
-values to be added.
-When eliminating duplicate values,
-any construction variables that end with
-the string
-.B PATH
-keep the left-most unique value.
-All other construction variables keep
-the right-most unique value.
-
-Examples:
-
-.ES
-# Add an optimization flag to $CCFLAGS.
-env.MergeFlags('-O3')
-
-# Combine the flags returned from running pkg-config with an optimization
-# flag and merge the result into the construction variables.
-env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3'])
-
-# Combine an optimization flag with the flags returned from running pkg-config
-# twice and merge the result into the construction variables.
-env.MergeFlags(['-O3',
-               '!pkg-config gtk+-2.0 --cflags --libs',
-               '!pkg-config libpng12 --cflags --libs'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI NoCache( target ", ...)"
-.TP
-.RI env.NoCache( target ", ...)"
-Specifies a list of files which should
-.I not
-be cached whenever the
-.BR CacheDir ()
-method has been activated.
-The specified targets may be a list
-or an individual target.
-
-Multiple files should be specified
-either as separate arguments to the
-.BR NoCache ()
-method, or as a list.
-.BR NoCache ()
-will also accept the return value of any of the construction environment
-Builder methods.
-
-Calling
-.BR NoCache ()
-on directories and other non-File Node types has no effect because
-only File Nodes are cached.
-
-Examples:
-
-.ES
-NoCache('foo.elf')
-NoCache(env.Program('hello', 'hello.c'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI NoClean( target ", ...)"
-.TP
-.RI env.NoClean( target ", ...)"
-Specifies a list of files or directories which should
-.I not
-be removed whenever the targets (or their dependencies)
-are specified with the
-.B -c
-command line option.
-The specified targets may be a list
-or an individual target.
-Multiple calls to
-.BR NoClean ()
-are legal,
-and prevent each specified target
-from being removed by calls to the
-.B -c
-option.
-
-Multiple files or directories should be specified
-either as separate arguments to the
-.BR NoClean ()
-method, or as a list.
-.BR NoClean ()
-will also accept the return value of any of the construction environment
-Builder methods.
-
-Calling
-.BR NoClean ()
-for a target overrides calling
-.BR Clean ()
-for the same target,
-and any targets passed to both functions will
-.I not
-be removed by the
-.B -c
-option.
-
-Examples:
-
-.ES
-NoClean('foo.elf')
-NoClean(env.Program('hello', 'hello.c'))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.ParseConfig( command ", [" function ", " unique ])
-Calls the specified
-.I function
-to modify the environment as specified by the output of
-.I command .
-The default
-.I function
-is
-.BR env.MergeFlags (),
-which expects the output of a typical
-.I *-config command
-(for example,
-.BR gtk-config )
-and adds the options
-to the appropriate construction variables.
-By default,
-duplicate values are not
-added to any construction variables;
-you can specify
-.B unique=0
-to allow duplicate
-values to be added.
-
-Interpreted options
-and the construction variables they affect
-are as specified for the
-.BR env.ParseFlags ()
-method (which this method calls).
-See that method's description, below,
-for a table of options and construction variables.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI ParseDepends( filename ", [" must_exist ", " only_one ])
-.TP
-.RI env.ParseDepends( filename ", [" must_exist ", " only_one ])
-Parses the contents of the specified
-.I filename
-as a list of dependencies in the style of
-.BR Make
-or
-.BR mkdep ,
-and explicitly establishes all of the listed dependencies.
-
-By default,
-it is not an error
-if the specified
-.I filename
-does not exist.
-The optional
-.I must_exist
-argument may be set to a non-zero
-value to have
-scons
-throw an exception and
-generate an error if the file does not exist,
-or is otherwise inaccessible.
-
-The optional
-.I only_one
-argument may be set to a non-zero
-value to have
-scons
-thrown an exception and
-generate an error
-if the file contains dependency
-information for more than one target.
-This can provide a small sanity check
-for files intended to be generated
-by, for example, the
-.B gcc -M
-flag,
-which should typically only
-write dependency information for
-one output file into a corresponding
-.B .d
-file.
-
-The
-.I filename
-and all of the files listed therein
-will be interpreted relative to
-the directory of the
-.I SConscript
-file which calls the
-.B ParseDepends
-function.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.ParseFlags( flags ", ...)"
-Parses one or more strings containing
-typical command-line flags for GCC tool chains
-and returns a dictionary with the flag values
-separated into the appropriate SCons construction variables.
-This is intended as a companion to the
-.BR env.MergeFlags ()
-method, but allows for the values in the returned dictionary
-to be modified, if necessary,
-before merging them into the construction environment.
-(Note that
-.BR env.MergeFlags ()
-will call this method if its argument is not a dictionary,
-so it is usually not necessary to call
-.BR env.ParseFlags ()
-directly unless you want to manipulate the values.)
-
-If the first character in any string is
-an exclamation mark (!),
-the rest of the string is executed as a command,
-and the output from the command is
-parsed as GCC tool chain command-line flags
-and added to the resulting dictionary.
-
-Flag values are translated accordig to the prefix found,
-and added to the following construction variables:
-
-.ES
--arch               CCFLAGS, LINKFLAGS
--D                  CPPDEFINES
--framework          FRAMEWORKS
--frameworkdir=      FRAMEWORKPATH
--include            CCFLAGS
--isysroot           CCFLAGS, LINKFLAGS
--I                  CPPPATH
--l                  LIBS
--L                  LIBPATH
--mno-cygwin         CCFLAGS, LINKFLAGS
--mwindows           LINKFLAGS
--pthread            CCFLAGS, LINKFLAGS
--std=               CFLAGS
--Wa,                ASFLAGS, CCFLAGS
--Wl,-rpath=         RPATH
--Wl,-R,             RPATH
--Wl,-R              RPATH
--Wl,                LINKFLAGS
--Wp,                CPPFLAGS
--                   CCFLAGS
-+                   CCFLAGS, LINKFLAGS
-.EE
-
-.IP
-Any other strings not associated with options
-are assumed to be the names of libraries
-and added to the
-.B LIBS
-construction variable.
-
-Examples (all of which produce the same result):
-
-.ES
-dict = env.ParseFlags('-O2 -Dfoo -Dbar=1')
-dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1')
-dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1'])
-dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-env.Perforce()
-A factory function that
-returns a Builder object
-to be used to fetch source files
-from the Perforce source code management system.
-The returned Builder
-is intended to be passed to the
-.B SourceCode
-function.
-
-This function is deprecated.  For details, see the entry for the
-.B SourceCode
-function.
-
-Example:
-
-.ES
-env.SourceCode('.', env.Perforce())
-.EE
-.IP
-Perforce uses a number of external
-environment variables for its operation.
-Consequently, this function adds the
-following variables from the user's external environment
-to the construction environment's
-ENV dictionary:
-P4CHARSET,
-P4CLIENT,
-P4LANGUAGE,
-P4PASSWD,
-P4PORT,
-P4USER,
-SystemRoot,
-USER,
-and
-USERNAME.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Platform( string )
-Returns a callable object
-that can be used to initialize
-a construction environment using the
-platform keyword of the Environment() method.
-
-Example:
-
-.ES
-env = Environment(platform = Platform('win32'))
-.EE
-.TP
-.RI env.Platform( string )
-Applies the callable object for the specified platform
-.I string
-to the environment through which the method was called.
-
-.ES
-env.Platform('posix')
-.EE
-.IP
-Note that the
-.B win32
-platform adds the
-.B SystemDrive
-and
-.B SystemRoot
-variables from the user's external environment
-to the construction environment's
-.B ENV
-dictionary.
-This is so that any executed commands
-that use sockets to connect with other systems
-(such as fetching source files from
-external CVS repository specifications like
-.BR :pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons )
-will work on Windows systems.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Progress( callable ", [" interval ])
-.TP
-.RI Progress( string ", [" interval ", " file ", " overwrite ])
-.TP
-.RI Progress( list_of_strings ", [" interval ", " file ", " overwrite ])
-Allows SCons to show progress made during the build
-by displaying a string or calling a function while
-evaluating Nodes (e.g. files).
-
-If the first specified argument is a Python callable
-(a function or an object that has a
-.BR __call__ ()
-method),
-the function will be called
-once every
-.I interval
-times a Node is evaluated.
-The callable will be passed the evaluated Node
-as its only argument.
-(For future compatibility,
-it's a good idea to also add
-.B *args
-and
-.B **kw
-as arguments to your function or method.
-This will prevent the code from breaking
-if SCons ever changes the interface
-to call the function with additional arguments in the future.)
-
-An example of a simple custom progress function
-that prints a string containing the Node name
-every 10 Nodes:
-
-.ES
-def my_progress_function(node, *args, **kw):
-    print 'Evaluating node %s!' % node
-Progress(my_progress_function, interval=10)
-.EE
-.IP
-A more complicated example of a custom progress display object
-that prints a string containing a count
-every 100 evaluated Nodes.
-Note the use of
-.B \\\\r
-(a carriage return)
-at the end so that the string
-will overwrite itself on a display:
-
-.ES
-import sys
-class ProgressCounter(object):
-    count = 0
-    def __call__(self, node, *args, **kw):
-        self.count += 100
-        sys.stderr.write('Evaluated %s nodes\\r' % self.count)
-Progress(ProgressCounter(), interval=100)
-.EE
-.IP
-If the first argument
-.BR Progress ()
-is a string,
-the string will be displayed
-every
-.I interval
-evaluated Nodes.
-The default is to print the string on standard output;
-an alternate output stream
-may be specified with the
-.B file=
-argument.
-The following will print a series of dots
-on the error output,
-one dot for every 100 evaluated Nodes:
-
-.ES
-import sys
-Progress('.', interval=100, file=sys.stderr)
-.EE
-.IP
-If the string contains the verbatim substring
-.B $TARGET,
-it will be replaced with the Node.
-Note that, for performance reasons, this is
-.I not
-a regular SCons variable substition,
-so you can not use other variables
-or use curly braces.
-The following example will print the name of
-every evaluated Node,
-using a
-.B \\\\r
-(carriage return) to cause each line to overwritten by the next line,
-and the
-.B overwrite=
-keyword argument to make sure the previously-printed
-file name is overwritten with blank spaces:
-
-.ES
-import sys
-Progress('$TARGET\\r', overwrite=True)
-.EE
-.IP
-If the first argument to
-.BR Progress ()
-is a list of strings,
-then each string in the list will be displayed
-in rotating fashion every
-.I interval
-evaluated Nodes.
-This can be used to implement a "spinner"
-on the user's screen as follows:
-
-.ES
-Progress(['-\\r', '\\\\\\r', '|\\r', '/\\r'], interval=5)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Precious( target ", ...)"
-.TP
-.RI env.Precious( target ", ...)"
-Marks each given
-.I target
-as precious so it is not deleted before it is rebuilt. Normally
-.B scons
-deletes a target before building it.
-Multiple targets can be passed in to a single call to
-.BR Precious ().
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Prepend( key = val ", [...])"
-Appends the specified keyword arguments
-to the beginning of construction variables in the environment.
-If the Environment does not have
-the specified construction variable,
-it is simply added to the environment.
-If the values of the construction variable
-and the keyword argument are the same type,
-then the two values will be simply added together.
-Otherwise, the construction variable
-and the value of the keyword argument
-are both coerced to lists,
-and the lists are added together.
-(See also the Append method, above.)
-
-Example:
-
-.ES
-env.Prepend(CCFLAGS = '-g ', FOO = ['foo.yyy'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.PrependENVPath( name ", " newpath ", [" envname ", " sep ", " delete_existing ])
-This appends new path elements to the given path in the
-specified external environment
-.RB ( ENV
-by default).
-This will only add
-any particular path once (leaving the first one it encounters and
-ignoring the rest, to preserve path order),
-and to help assure this,
-will normalize all paths (using
-.B os.path.normpath
-and
-.BR os.path.normcase ).
-This can also handle the
-case where the given old path variable is a list instead of a
-string, in which case a list will be returned instead of a string.
-
-If
-.I delete_existing
-is 0, then adding a path that already exists
-will not move it to the beginning;
-it will stay where it is in the list.
-
-Example:
-
-.ES
-print 'before:',env['ENV']['INCLUDE']
-include_path = '/foo/bar:/foo'
-env.PrependENVPath('INCLUDE', include_path)
-print 'after:',env['ENV']['INCLUDE']
-.EE
-
-The above exmaple will print:
-
-.ES
-before: /biz:/foo
-after: /foo/bar:/foo:/biz
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.PrependUnique( key = val ", delete_existing=0, [...])"
-Appends the specified keyword arguments
-to the beginning of construction variables in the environment.
-If the Environment does not have
-the specified construction variable,
-it is simply added to the environment.
-If the construction variable being appended to is a list,
-then any value(s) that already exist in the
-construction variable will
-.I not
-be added again to the list.
-However, if delete_existing is 1, 
-existing matching values are removed first, so
-existing values in the arg list move to the front of the list.
-
-Example:
-
-.ES
-env.PrependUnique(CCFLAGS = '-g', FOO = ['foo.yyy'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-env.RCS()
-A factory function that
-returns a Builder object
-to be used to fetch source files
-from RCS.
-The returned Builder
-is intended to be passed to the
-.B SourceCode
-function:
-
-This function is deprecated.  For details, see the entry for the
-.B SourceCode
-function.
-
-Examples:
-
-.ES
-env.SourceCode('.', env.RCS())
-.EE
-.IP
-Note that
-.B scons
-will fetch source files
-from RCS subdirectories automatically,
-so configuring RCS
-as demonstrated in the above example
-should only be necessary if
-you are fetching from
-RCS,v
-files in the same
-directory as the source files,
-or if you need to explicitly specify RCS
-for a specific subdirectory.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.Replace( key = val ", [...])"
-Replaces construction variables in the Environment
-with the specified keyword arguments.
-
-Example:
-
-.ES
-env.Replace(CCFLAGS = '-g', FOO = 'foo.xxx')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Repository( directory )
-.TP
-.RI env.Repository( directory )
-Specifies that
-.I directory
-is a repository to be searched for files.
-Multiple calls to
-.BR Repository ()
-are legal,
-and each one adds to the list of
-repositories that will be searched.
-
-To
-.BR scons ,
-a repository is a copy of the source tree,
-from the top-level directory on down,
-which may contain
-both source files and derived files
-that can be used to build targets in
-the local source tree.
-The canonical example would be an
-official source tree maintained by an integrator.
-If the repository contains derived files,
-then the derived files should have been built using
-.BR scons ,
-so that the repository contains the necessary
-signature information to allow
-.B scons
-to figure out when it is appropriate to
-use the repository copy of a derived file,
-instead of building one locally.
-
-Note that if an up-to-date derived file
-already exists in a repository,
-.B scons
-will
-.I not
-make a copy in the local directory tree.
-In order to guarantee that a local copy
-will be made,
-use the
-.B Local()
-method.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Requires( target ", " prerequisite )
-.TP
-.RI env.Requires( target ", " prerequisite )
-Specifies an order-only relationship
-between the specified target file(s)
-and the specified prerequisite file(s).
-The prerequisite file(s)
-will be (re)built, if necessary,
-.I before
-the target file(s),
-but the target file(s) do not actually
-depend on the prerequisites
-and will not be rebuilt simply because
-the prerequisite file(s) change.
-
-Example:
-
-.ES
-env.Requires('foo', 'file-that-must-be-built-before-foo')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Return([ vars "... , " stop= ])
-By default,
-this stops processing the current SConscript
-file and returns to the calling SConscript file
-the values of the variables named in the
-.I vars
-string arguments.
-Multiple strings contaning variable names may be passed to
-.BR Return ().
-Any strings that contain white space
-
-The optional
-.B stop=
-keyword argument may be set to a false value
-to continue processing the rest of the SConscript
-file after the
-.BR Return ()
-call.
-This was the default behavior prior to SCons 0.98.
-However, the values returned
-are still the values of the variables in the named
-.I vars
-at the point
-.BR Return ()
-is called.
-
-Examples:
-
-.ES
-# Returns without returning a value.
-Return()
-
-# Returns the value of the 'foo' Python variable.
-Return("foo")
-
-# Returns the values of the Python variables 'foo' and 'bar'.
-Return("foo", "bar")
-
-# Returns the values of Python variables 'val1' and 'val2'.
-Return('val1 val2')
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Scanner( function ", [" argument ", " keys ", " path_function ", " node_class ", " node_factory ", " scan_check ", " recursive ])
-.TP
-.RI env.Scanner( function ", [" argument ", " keys ", " path_function ", " node_class ", " node_factory ", " scan_check ", " recursive ])
-Creates a Scanner object for
-the specified
-.IR function .
-See the section "Scanner Objects,"
-below, for a complete explanation of the arguments and behavior.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-env.SCCS()
-A factory function that
-returns a Builder object
-to be used to fetch source files
-from SCCS.
-The returned Builder
-is intended to be passed to the
-.B SourceCode
-function.
-
-This function is deprecated.  For details, see the entry for the
-.B SourceCode
-function.
-
-Example:
-
-.ES
-env.SourceCode('.', env.SCCS())
-.EE
-.IP
-Note that
-.B scons
-will fetch source files
-from SCCS subdirectories automatically,
-so configuring SCCS
-as demonstrated in the above example
-should only be necessary if
-you are fetching from
-.I s.SCCS
-files in the same
-directory as the source files,
-or if you need to explicitly specify SCCS
-for a specific subdirectory.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SConscript( scripts ", [" exports ", " variant_dir ", " duplicate ])
-'\" .RI SConscript( scripts ", [" exports ", " variant_dir ", " src_dir ", " duplicate ])
-.TP
-.RI env.SConscript( scripts ", [" exports ", " variant_dir ", " duplicate ])
-'\" .RI env.SConscript( scripts ", [" exports ", " variant_dir ", " src_dir ", " duplicate ])
-.TP
-.RI SConscript(dirs= subdirs ", [name=" script ", " exports ", " variant_dir ", " duplicate ])
-'\" .RI SConscript(dirs= subdirs ", [name=" script ", " exports ", " variant_dir ", " src_dir ", " duplicate ])
-.TP
-.RI env.SConscript(dirs= subdirs ", [name=" script ", " exports ", " variant_dir ", " duplicate ])
-'\" .RI env.SConscript(dirs= subdirs ", [name=" script ", " exports ", " variant_dir ", " src_dir ", " duplicate ])
-This tells
-.B scons
-to execute
-one or more subsidiary SConscript (configuration) files.
-Any variables returned by a called script using
-.BR Return ()
-will be returned by the call to
-.BR SConscript ().
-There are two ways to call the
-.BR SConscript ()
-function.
-
-The first way you can call
-.BR SConscript ()
-is to explicitly specify one or more
-.I scripts
-as the first argument.
-A single script may be specified as a string;
-multiple scripts must be specified as a list
-(either explicitly or as created by
-a function like
-.BR Split ()).
-Examples:
-.ES
-SConscript('SConscript')      # run SConscript in the current directory
-SConscript('src/SConscript')  # run SConscript in the src directory
-SConscript(['src/SConscript', 'doc/SConscript'])
-config = SConscript('MyConfig.py')
-.EE
-
-.IP
-The second way you can call
-.BR SConscript ()
-is to specify a list of (sub)directory names
-as a
-.RI dirs= subdirs
-keyword argument.
-In this case,
-.B scons
-will, by default,
-execute a subsidiary configuration file named
-.B SConscript
-in each of the specified directories.
-You may specify a name other than
-.B SConscript
-by supplying an optional
-.RI name= script
-keyword argument.
-The first three examples below have the same effect
-as the first three examples above:
-.ES
-SConscript(dirs='.')      # run SConscript in the current directory
-SConscript(dirs='src')    # run SConscript in the src directory
-SConscript(dirs=['src', 'doc'])
-SConscript(dirs=['sub1', 'sub2'], name='MySConscript')
-.EE
-
-.IP
-The optional
-.I exports
-argument provides a list of variable names or a dictionary of
-named values to export to the
-.IR script(s) .
-These variables are locally exported only to the specified
-.IR script(s) ,
-and do not affect the global pool of variables used by the
-.BR Export ()
-function.
-'\"If multiple dirs are provided, each script gets a fresh export.
-The subsidiary
-.I script(s)
-must use the
-.BR Import ()
-function to import the variables.
-Examples:
-.ES
-foo = SConscript('sub/SConscript', exports='env')
-SConscript('dir/SConscript', exports=['env', 'variable'])
-SConscript(dirs='subdir', exports='env variable')
-SConscript(dirs=['one', 'two', 'three'], exports='shared_info')
-.EE
-
-.IP
-If the optional
-.I variant_dir
-argument is present, it causes an effect equivalent to the
-.BR VariantDir ()
-method described below.
-(If
-.I variant_dir
-is not present, the
-'\" .IR src_dir and
-.I duplicate
-'\" arguments are ignored.)
-argument is ignored.)
-The
-.I variant_dir
-'\" and
-'\" .I src_dir
-'\" arguments are interpreted relative to the directory of the calling
-argument is interpreted relative to the directory of the calling
-.B SConscript
-file.
-See the description of the
-.BR VariantDir ()
-function below for additional details and restrictions.
-
-.IP
-If
-.I variant_dir
-is present,
-'\" but
-'\" .IR src_dir " is not,"
-the source directory is the directory in which the
-.B SConscript
-file resides and the
-.B SConscript
-file is evaluated as if it were in the
-.I variant_dir
-directory:
-.ES
-SConscript('src/SConscript', variant_dir = 'build')
-.EE
-is equivalent to
-.ES
-VariantDir('build', 'src')
-SConscript('build/SConscript')
-.EE
-This later paradigm is often used when the sources are
-in the same directory as the
-.BR SConstruct:
-.ES
-SConscript('SConscript', variant_dir = 'build')
-.EE
-is equivalent to
-.ES
-VariantDir('build', '.')
-SConscript('build/SConscript')
-.EE
-
-'\" If
-'\" .IR variant_dir " and"
-'\" .IR src_dir " are both present,"
-'\" xxxxx everything is in a state of confusion.
-'\" .ES
-'\" SConscript(dirs = 'src', variant_dir = 'build', src_dir = '.')
-'\" runs src/SConscript in build/src, but
-'\" SConscript(dirs = 'lib', variant_dir = 'build', src_dir = 'src')
-'\" runs lib/SConscript (in lib!).  However,
-'\" SConscript(dirs = 'src', variant_dir = 'build', src_dir = 'src')
-'\" runs src/SConscript in build.  Moreover,
-'\" SConscript(dirs = 'src/lib', variant_dir = 'build', src_dir = 'src')
-'\" runs src/lib/SConscript in build/lib.  Moreover,
-'\" SConscript(dirs = 'build/src/lib', variant_dir = 'build', src_dir = 'src')
-'\" can't find build/src/lib/SConscript, even though it ought to exist.
-'\" .EE
-'\" is equivalent to
-'\" .ES
-'\" ????????????????
-'\" .EE
-'\" and what about this alternative?
-'\"TODO??? SConscript('build/SConscript', src_dir='src')
-
-.IP
-Here are some composite examples:
-
-.ES
-# collect the configuration information and use it to build src and doc
-shared_info = SConscript('MyConfig.py')
-SConscript('src/SConscript', exports='shared_info')
-SConscript('doc/SConscript', exports='shared_info')
-.EE
-
-.ES
-# build debugging and production versions.  SConscript
-# can use Dir('.').path to determine variant.
-SConscript('SConscript', variant_dir='debug', duplicate=0)
-SConscript('SConscript', variant_dir='prod', duplicate=0)
-.EE
-
-.ES
-# build debugging and production versions.  SConscript
-# is passed flags to use.
-opts = { 'CPPDEFINES' : ['DEBUG'], 'CCFLAGS' : '-pgdb' }
-SConscript('SConscript', variant_dir='debug', duplicate=0, exports=opts)
-opts = { 'CPPDEFINES' : ['NODEBUG'], 'CCFLAGS' : '-O' }
-SConscript('SConscript', variant_dir='prod', duplicate=0, exports=opts)
-.EE
-
-.ES
-# build common documentation and compile for different architectures
-SConscript('doc/SConscript', variant_dir='build/doc', duplicate=0)
-SConscript('src/SConscript', variant_dir='build/x86', duplicate=0)
-SConscript('src/SConscript', variant_dir='build/ppc', duplicate=0)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SConscriptChdir( value )
-.TP
-.RI env.SConscriptChdir( value )
-By default,
-.B scons
-changes its working directory
-to the directory in which each
-subsidiary SConscript file lives.
-This behavior may be disabled
-by specifying either:
-
-.ES
-SConscriptChdir(0)
-env.SConscriptChdir(0)
-.EE
-.IP
-in which case
-.B scons
-will stay in the top-level directory
-while reading all SConscript files.
-(This may be necessary when building from repositories,
-when all the directories in which SConscript files may be found
-don't necessarily exist locally.)
-You may enable and disable
-this ability by calling
-SConscriptChdir()
-multiple times.
-
-Example:
-
-.ES
-env = Environment()
-SConscriptChdir(0)
-SConscript('foo/SConscript')	# will not chdir to foo
-env.SConscriptChdir(1)
-SConscript('bar/SConscript')	# will chdir to bar
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SConsignFile([ file , dbm_module ])
-.TP
-.RI env.SConsignFile([ file , dbm_module ])
-This tells
-.B scons
-to store all file signatures
-in the specified database
-.IR file .
-If the
-.I file
-name is omitted,
-.B .sconsign
-is used by default.
-(The actual file name(s) stored on disk
-may have an appropriated suffix appended
-by the
-.IR  dbm_module .)
-If
-.I file
-is not an absolute path name,
-the file is placed in the same directory as the top-level
-.B SConstruct
-file.
-
-If
-.I file
-is
-.BR None ,
-then
-.B scons
-will store file signatures
-in a separate
-.B .sconsign
-file in each directory,
-not in one global database file.
-(This was the default behavior
-prior to SCons 0.96.91 and 0.97.)
-
-The optional
-.I dbm_module
-argument can be used to specify
-which Python database module
-The default is to use a custom
-.B SCons.dblite
-module that uses pickled
-Python data structures,
-and which works on all Python versions.
-
-Examples:
-
-.ES
-# Explicitly stores signatures in ".sconsign.dblite"
-# in the top-level SConstruct directory (the
-# default behavior).
-SConsignFile()
-
-# Stores signatures in the file "etc/scons-signatures"
-# relative to the top-level SConstruct directory.
-SConsignFile("etc/scons-signatures")
-
-# Stores signatures in the specified absolute file name.
-SConsignFile("/home/me/SCons/signatures")
-
-# Stores signatures in a separate .sconsign file
-# in each directory.
-SConsignFile(None)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.SetDefault(key = val ", [...])"
-Sets construction variables to default values specified with the keyword
-arguments if (and only if) the variables are not already set.
-The following statements are equivalent:
-
-.ES
-env.SetDefault(FOO = 'foo')
-
-if 'FOO' not in env: env['FOO'] = 'foo'
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SetOption( name ", " value )
-.TP
-.RI env.SetOption( name ", " value )
-This function provides a way to set a select subset of the scons command
-line options from a SConscript file. The options supported are:
-
-.RS 10
-.TP 6
-.B clean
-which corresponds to -c, --clean and --remove;
-.TP 6
-.B duplicate
-which corresponds to --duplicate;
-.TP 6
-.B help
-which corresponds to -h and --help;
-.TP 6
-.B implicit_cache
-which corresponds to --implicit-cache;
-.TP 6
-.B max_drift
-which corresponds to --max-drift;
-.TP 6
-.B no_exec
-which corresponds to -n, --no-exec, --just-print, --dry-run and --recon;
-.TP 6
-.B num_jobs
-which corresponds to -j and --jobs;
-.TP 6
-.B random
-which corresponds to --random; and
-.TP 6
-.B stack_size
-which corresponds to --stack-size.
-.RE
-
-.IP
-See the documentation for the
-corresponding command line object for information about each specific
-option.
-
-Example:
-
-.ES
-SetOption('max_drift', 1)
-.EE
-
+'\" BEGIN GENERATED FUNCTION DESCRIPTIONS
 '\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SideEffect( side_effect ", " target )
-.TP
-.RI env.SideEffect( side_effect ", " target )
-Declares
-.I side_effect
-as a side effect of building
-.IR target .
-Both
-.I side_effect
-and
-.I target
-can be a list, a file name, or a node.
-A side effect is a target file that is created or updated
-as a side effect of building other targets.
-For example, a Windows PDB
-file is created as a side effect of building the .obj
-files for a static library,
-and various log files are created updated
-as side effects of various TeX commands.
-If a target is a side effect of multiple build commands,
-.B scons
-will ensure that only one set of commands
-is executed at a time.
-Consequently, you only need to use this method
-for side-effect targets that are built as a result of
-multiple build commands.
-
-Because multiple build commands may update
-the same side effect file,
-by default the
-.I side_effect
-target is
-.I not
-automatically removed
-when the
-.I target
-is removed by the
-.B -c
-option.
-(Note, however, that the
-.I side_effect
-might be removed as part of
-cleaning the directory in which it lives.)
-If you want to make sure the
-.I side_effect
-is cleaned whenever a specific
-.I target
-is cleaned,
-you must specify this explicitly
-with the
-.BR Clean ()
-or
-.BR env.Clean ()
-function.
-
+.so functions.man
 '\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SourceCode( entries ", " builder )
-.TP
-.RI env.SourceCode( entries ", " builder )
-This function and its associate factory functions are deprecated.
-There is no replacement.
-The intended use was to keep a local tree in sync with an archive,
-but in actuality the function only causes the archive
-to be fetched on the first run.
-Synchronizing with the archive is best done external to SCons.
-
-Arrange for non-existent source files to
-be fetched from a source code management system
-using the specified
-.IR builder .
-The specified
-.I entries
-may be a Node, string or list of both,
-and may represent either individual
-source files or directories in which
-source files can be found.
-
-For any non-existent source files,
-.B scons
-will search up the directory tree
-and use the first
-.B SourceCode
-builder it finds.
-The specified
-.I builder
-may be
-.BR None ,
-in which case
-.B scons
-will not use a builder to fetch
-source files for the specified
-.IR entries ,
-even if a
-.B SourceCode
-builder has been specified
-for a directory higher up the tree.
-
-.B scons
-will, by default,
-fetch files from SCCS or RCS subdirectories
-without explicit configuration.
-This takes some extra processing time
-to search for the necessary
-source code management files on disk.
-You can avoid these extra searches
-and speed up your build a little
-by disabling these searches as follows:
-
-.ES
-env.SourceCode('.', None)
-.EE
-
-.IP
-Note that if the specified
-.I builder
-is one you create by hand,
-it must have an associated
-construction environment to use
-when fetching a source file.
-
-.B scons
-provides a set of canned factory
-functions that return appropriate
-Builders for various popular
-source code management systems.
-Canonical examples of invocation include:
-
-.ES
-env.SourceCode('.', env.BitKeeper('/usr/local/BKsources'))
-env.SourceCode('src', env.CVS('/usr/local/CVSROOT'))
-env.SourceCode('/', env.RCS())
-env.SourceCode(['f1.c', 'f2.c'], env.SCCS())
-env.SourceCode('no_source.c', None)
-.EE
-'\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion'))
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI env.subst( input ", [" raw ", " target ", " source ", " conv ])
-Performs construction variable interpolation
-on the specified string or sequence argument
-.IR input .
-
-By default,
-leading or trailing white space will
-be removed from the result.
-and all sequences of white space
-will be compressed to a single space character.
-Additionally, any
-.B $(
-and
-.B $)
-character sequences will be stripped from the returned string,
-The optional
-.I raw
-argument may be set to
-.B 1
-if you want to preserve white space and
-.BR $( - $)
-sequences.
-The
-.I raw
-argument may be set to
-.B 2
-if you want to strip
-all characters between
-any
-.B $(
-and
-.B $)
-pairs
-(as is done for signature calculation).
-
-If the input is a sequence
-(list or tuple),
-the individual elements of
-the sequence will be expanded,
-and the results will be returned as a list.
-
-The optional
-.I target
-and
-.I source
-keyword arguments
-must be set to lists of
-target and source nodes, respectively,
-if you want the
-.BR $TARGET ,
-.BR $TARGETS ,
-.BR $SOURCE
-and
-.BR $SOURCES
-to be available for expansion.
-This is usually necessary if you are
-calling
-.BR env.subst ()
-from within a Python function used
-as an SCons action.
-
-Returned string values or sequence elements
-are converted to their string representation by default.
-The optional
-.I conv
-argument
-may specify a conversion function
-that will be used in place of
-the default.
-For example, if you want Python objects
-(including SCons Nodes)
-to be returned as Python objects,
-you can use the Python
-.B lambda
-idiom to pass in an unnamed function
-that simply returns its unconverted argument.
-
-Example:
-
-.ES
-print env.subst("The C compiler is: $CC")
-
-def compile(target, source, env):
-    sourceDir = env.subst("${SOURCE.srcdir}",
-                          target=target,
-                          source=source)
-
-source_nodes = env.subst('$EXPAND_TO_NODELIST',
-                         conv=lambda x: x)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-'\".TP
-'\".RI Subversion( repository ", " module )
-'\"A factory function that
-'\"returns a Builder object
-'\"to be used to fetch source files
-'\"from the specified Subversion
-'\".IR repository .
-'\"The returned Builder
-'\"is intended to be passed to the
-'\".B SourceCode
-'\"function.
-'\"
-'\"The optional specified
-'\".I module
-'\"will be added to the beginning
-'\"of all repository path names;
-'\"this can be used, in essence,
-'\"to strip initial directory names
-'\"from the repository path names,
-'\"so that you only have to
-'\"replicate part of the repository
-'\"directory hierarchy in your
-'\"local build directory.
-'\"
-'\"This function is deprecated.  For details, see the entry for the
-'\".B SourceCode
-'\"function.
-'\"
-'\"Example:
+'\" END GENERATED FUNCTION DESCRIPTIONS
 '\"
-'\".ES
-'\"# Will fetch foo/bar/src.c
-'\"# from /usr/local/Subversion/foo/bar/src.c.
-'\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion'))
-'\"
-'\"# Will fetch bar/src.c
-'\"# from /usr/local/Subversion/foo/bar/src.c.
-'\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion', 'foo'))
+'\" The descriptions above of the various SCons functions are generated
+'\" from the .xml files that live next to the various Python modules in
+'\" the build enginer library.  If you're reading this [gnt]roff file
+'\" with an eye towards patching this man page, you can still submit
+'\" a diff against this text, but it will have to be translated to a
+'\" diff against the underlying .xml file before the patch is actually
+'\" accepted.  If you do that yourself, it will make it easier to
+'\" integrate the patch.
 '\"
-'\"# Will fetch src.c
-'\"# from /usr/local/Subversion/foo/bar/src.c.
-'\"env.SourceCode('.', env.Subversion('file:///usr/local/Subversion', 'foo/bar'))
-'\".EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI SourceSignatures( type )
-.TP
-.RI env.SourceSignatures( type )
-Note:  Although it is not yet officially deprecated,
-use of this function is discouraged.
-See the
-.BR Decider ()
-function for a more flexible and straightforward way
-to configure SCons' decision-making.
-
-The
-.BR SourceSignatures ()
-function tells
-.B scons
-how to decide if a source file
-(a file that is not built from any other files)
-has changed since the last time it
-was used to build a particular target file.
-Legal values are
-.B "MD5"
-or
-.BR "timestamp" .
-
-If the environment method is used,
-the specified type of source signature
-is only used when deciding whether targets
-built with that environment are up-to-date or must be rebuilt.
-If the global function is used,
-the specified type of source signature becomes the default
-used for all decisions
-about whether targets are up-to-date.
-
-.B "MD5"
-means
-.B scons
-decides that a source file has changed
-if the MD5 checksum of its contents has changed since
-the last time it was used to rebuild a particular target file.
-
-.B "timestamp"
-means
-.B scons
-decides that a source file has changed
-if its timestamp (modification time) has changed since
-the last time it was used to rebuild a particular target file.
-(Note that although this is similar to the behavior of Make,
-by default it will also rebuild if the dependency is
-.I older
-than the last time it was used to rebuild the target file.)
-
-There is no different between the two behaviors
-for Python
-.BR Value ()
-node objects.
-
-.B "MD5"
-signatures take longer to compute,
-but are more accurate than
-.B "timestamp"
-signatures.
-The default value is
-.BR "MD5" .
-
-Note that the default
-.BR TargetSignatures ()
-setting (see below)
-is to use this
-.BR SourceSignatures ()
-setting for any target files that are used
-to build other target files.
-Consequently, changing the value of
-.BR SourceSignatures ()
-will, by default,
-affect the up-to-date decision for all files in the build
-(or all files built with a specific construction environment
-when
-.BR env.SourceSignatures ()
-is used).
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Split( arg )
-.TP
-.RI env.Split( arg )
-Returns a list of file names or other objects.
-If arg is a string,
-it will be split on strings of white-space characters
-within the string,
-making it easier to write long lists of file names.
-If arg is already a list,
-the list will be returned untouched.
-If arg is any other type of object,
-it will be returned as a list
-containing just the object.
-
-Example:
-
-.ES
-files = Split("f1.c f2.c f3.c")
-files = env.Split("f4.c f5.c f6.c")
-files = Split("""
-	f7.c
-	f8.c
-	f9.c
-""")
-.EE
-
+'\" END GENERATED FUNCTION DESCRIPTIONS
 '\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Tag( node ", " tags )
-Annotates file or directory Nodes with
-information about how the
-.BR Package ()
-Builder should package those files or directories.
-All tags are optional.
-
-Examples:
-
-.ES
-# makes sure the built library will be installed with 0644 file
-# access mode
-Tag( Library( 'lib.c' ), UNIX_ATTR="0644" )
-
-# marks file2.txt to be a documentation file
-Tag( 'file2.txt', DOC )
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI TargetSignatures( type )
-.TP
-.RI env.TargetSignatures( type )
-Note:  Although it is not yet officially deprecated,
-use of this function is discouraged.
-See the
-.BR Decider ()
-function for a more flexible and straightforward way
-to configure SCons' decision-making.
-
-The
-.BR TargetSignatures ()
-function tells
-.B scons
-how to decide if a target file
-(a file that
-.I is
-built from any other files)
-has changed since the last time it
-was used to build some other target file.
-Legal values are
-.BR "build" ;
-.BR "content"
-(or its synonym
-.BR "MD5" );
-.BR "timestamp" ;
-or
-.BR "source" .
-
-If the environment method is used,
-the specified type of target signature is only used
-for targets built with that environment.
-If the global function is used,
-the specified type of signature becomes the default
-used for all target files that
-don't have an explicit target signature type
-specified for their environments.
-
-.B "content"
-(or its synonym
-.BR "MD5" )
-means
-.B scons
-decides that a target file has changed
-if the MD5 checksum of its contents has changed since
-the last time it was used to rebuild some other target file.
-This means
-.B scons
-will open up
-MD5 sum the contents
-of target files after they're built,
-and may decide that it does not need to rebuild
-"downstream" target files if a file was
-rebuilt with exactly the same contents as the last time.
-
-.B "timestamp"
-means
-.B scons
-decides that a target file has changed
-if its timestamp (modification time) has changed since
-the last time it was used to rebuild some other target file.
-(Note that although this is similar to the behavior of Make,
-by default it will also rebuild if the dependency is
-.I older
-than the last time it was used to rebuild the target file.)
-
-.B "source"
-means
-.B scons
-decides that a target file has changed
-as specified by the corresponding
-.BR SourceSignatures ()
-setting
-.BR "" ( "MD5"
-or
-.BR "timestamp" ).
-This means that
-.B scons
-will treat all input files to a target the same way,
-regardless of whether they are source files
-or have been built from other files.
-
-.B "build"
-means
-.B scons
-decides that a target file has changed
-if it has been rebuilt in this invocation
-or if its content or timestamp have changed
-as specified by the corresponding
-.BR SourceSignatures ()
-setting.
-This "propagates" the status of a rebuilt file
-so that other "downstream" target files
-will always be rebuilt,
-even if the contents or the timestamp
-have not changed.
-
-.B "build"
-signatures are fastest because
-.B "content"
-(or
-.BR "MD5" )
-signatures take longer to compute,
-but are more accurate than
-.B "timestamp"
-signatures,
-and can prevent unnecessary "downstream" rebuilds
-when a target file is rebuilt to the exact same contents
-as the previous build.
-The
-.B "source"
-setting provides the most consistent behavior
-when other target files may be rebuilt from
-both source and target input files.
-The default value is
-.BR "source" .
-
-Because the default setting is
-.BR "source" ,
-using
-.BR SourceSignatures ()
-is generally preferable to
-.BR TargetSignatures () ,
-so that the up-to-date decision
-will be consistent for all files
-(or all files built with a specific construction environment).
-Use of
-.BR TargetSignatures ()
-provides specific control for how built target files
-affect their "downstream" dependencies.
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Tool( string [, toolpath ", " **kw ])
-Returns a callable object
-that can be used to initialize
-a construction environment using the
-tools keyword of the Environment() method.
-The object may be called with a construction
-environment as an argument,
-in which case the object will
-add the necessary variables
-to the construction environment
-and the name of the tool will be added to the
-.B $TOOLS
-construction variable.
-
-Additional keyword arguments are passed to the tool's
-.B generate()
-method.
-
-Examples:
-
-.ES
-env = Environment(tools = [ Tool('msvc') ])
-
-env = Environment()
-t = Tool('msvc')
-t(env)  # adds 'msvc' to the TOOLS variable
-u = Tool('opengl', toolpath = ['tools'])
-u(env)  # adds 'opengl' to the TOOLS variable
-.EE
-.TP
-.RI env.Tool( string [, toolpath ", " **kw ])
-Applies the callable object for the specified tool
-.I string
-to the environment through which the method was called.
-
-Additional keyword arguments are passed to the tool's
-.B generate()
-method.
-
-.ES
-env.Tool('gcc')
-env.Tool('opengl', toolpath = ['build/tools'])
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI Value( value ", [" built_value ])
-.TP
-.RI env.Value( value ", [" built_value ])
-Returns a Node object representing the specified Python value.  Value
-Nodes can be used as dependencies of targets.  If the result of
-calling
-.BR str( value )
-changes between SCons runs, any targets depending on
-.BR Value( value )
-will be rebuilt.
-(This is true even when using timestamps to decide if
-files are up-to-date.)
-When using timestamp source signatures, Value Nodes'
-timestamps are equal to the system time when the Node is created.
-
-The returned Value Node object has a
-.BR write ()
-method that can be used to "build" a Value Node
-by setting a new value.
-The optional
-.I built_value
-argument can be specified
-when the Value Node is created
-to indicate the Node should already be considered
-"built."
-There is a corresponding
-.BR read ()
-method that will return the built value of the Node.
-
-Examples:
-
-.ES
-env = Environment()
-
-def create(target, source, env):
-    # A function that will write a 'prefix=$SOURCE'
-    # string into the file name specified as the
-    # $TARGET.
-    f = open(str(target[0]), 'wb')
-    f.write('prefix=' + source[0].get_contents())
-
-# Fetch the prefix= argument, if any, from the command
-# line, and use /usr/local as the default.
-prefix = ARGUMENTS.get('prefix', '/usr/local')
-
-# Attach a .Config() builder for the above function action
-# to the construction environment.
-env['BUILDERS']['Config'] = Builder(action = create)
-env.Config(target = 'package-config', source = Value(prefix))
-
-def build_value(target, source, env):
-    # A function that "builds" a Python Value by updating
-    # the the Python value with the contents of the file
-    # specified as the source of the Builder call ($SOURCE).
-    target[0].write(source[0].get_contents())
-
-output = env.Value('before')
-input = env.Value('after')
-
-# Attach a .UpdateValue() builder for the above function
-# action to the construction environment.
-env['BUILDERS']['UpdateValue'] = Builder(action = build_value)
-env.UpdateValue(target = Value(output), source = Value(input))
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI VariantDir( variant_dir ", " src_dir ", [" duplicate ])
-.TP
-.RI env.VariantDir( variant_dir ", " src_dir ", [" duplicate ])
-Use the
-.BR VariantDir ()
-function to create a copy of your sources in another location:
-if a name under
-.IR variant_dir
-is not found but exists under
-.IR src_dir ,
-the file or directory is copied to
-.IR variant_dir .
-Target files can be built in a different directory
-than the original sources by simply refering to the sources (and targets)
-within the variant tree.
-
-.BR VariantDir ()
-can be called multiple times with the same
-.I  src_dir
-to set up multiple builds with different options
-.RI ( variants ).
-The
-.I src_dir
-location must be in or underneath the SConstruct file's directory, and
-.I variant_dir
-may not be underneath
-.IR src_dir .
-'\"TODO: Can the above restrictions be clarified or relaxed?
-'\"TODO: The latter restriction is clearly not completely right;
-'\"TODO: src_dir = '.' works fine with a build dir under it.
-
-The default behavior is for
-.B scons
-to physically duplicate the source files in the variant tree.
-Thus, a build performed in the variant tree is guaranteed to be identical
-to a build performed in the source tree even if
-intermediate source files are generated during the build,
-or preprocessors or other scanners search for included files
-relative to the source file,
-or individual compilers or other invoked tools are hard-coded
-to put derived files in the same directory as source files.
-
-If possible on the platform,
-the duplication is performed by linking rather than copying;
-see also the
-.IR --duplicate
-command-line option.
-Moreover, only the files needed for the build are duplicated;
-files and directories that are not used are not present in
-.IR variant_dir .
-
-Duplicating the source tree may be disabled by setting the
-.I duplicate
-argument to 0 (zero).
-This will cause
-.B scons
-to invoke Builders using the path names of source files in
-.I src_dir
-and the path names of derived files within
-.IR variant_dir .
-This is always more efficient than
-.IR duplicate =1,
-and is usually safe for most builds
-(but see above for cases that may cause problems).
-
-Note that
-.BR VariantDir ()
-works most naturally with a subsidiary SConscript file.
-However, you would then call the subsidiary SConscript file
-not in the source directory, but in the
-.I variant_dir ,
-regardless of the value of
-.IR duplicate .
-This is how you tell
-.B scons
-which variant of a source tree to build:
-
-.ES
-# run src/SConscript in two variant directories
-VariantDir('build/variant1', 'src')
-SConscript('build/variant1/SConscript')
-VariantDir('build/variant2', 'src')
-SConscript('build/variant2/SConscript')
-.EE
-
-.IP
-See also the
-.BR SConscript ()
-function, described above,
-for another way to specify a variant directory
-in conjunction with calling a subsidiary SConscript file.
-
-Examples:
-
-.ES
-# use names in the build directory, not the source directory
-VariantDir('build', 'src', duplicate=0)
-Program('build/prog', 'build/source.c')
-.EE
-
-.ES
-# this builds both the source and docs in a separate subtree
-VariantDir('build', '.', duplicate=0)
-SConscript(dirs=['build/src','build/doc'])
-.EE
-
-.ES
-# same as previous example, but only uses SConscript
-SConscript(dirs='src', variant_dir='build/src', duplicate=0)
-SConscript(dirs='doc', variant_dir='build/doc', duplicate=0)
-.EE
-
-'\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
-.TP
-.RI WhereIs( program ", [" path  ", " pathext ", " reject ])
-.TP
-.RI env.WhereIs( program ", [" path  ", " pathext ", " reject ])
-
-Searches for the specified executable
-.I program,
-returning the full path name to the program
-if it is found,
-and returning None if not.
-Searches the specified
-.I path,
-the value of the calling environment's PATH
-(env['ENV']['PATH']),
-or the user's current external PATH
-(os.environ['PATH'])
-by default.
-On Windows systems, searches for executable
-programs with any of the file extensions
-listed in the specified
-.I pathext,
-the calling environment's PATHEXT
-(env['ENV']['PATHEXT'])
-or the user's current PATHEXT
-(os.environ['PATHEXT'])
-by default.
-Will not select any
-path name or names
-in the specified
-.I reject
-list, if any.
 
 .SS SConscript Variables
 In addition to the global functions and methods,