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Diffstat (limited to 'doc/man/scons.xml')
| -rw-r--r-- | doc/man/scons.xml | 362 |
1 files changed, 211 insertions, 151 deletions
diff --git a/doc/man/scons.xml b/doc/man/scons.xml index faec455..c1773c7 100644 --- a/doc/man/scons.xml +++ b/doc/man/scons.xml @@ -1921,7 +1921,7 @@ These warnings are enabled by default.</para> <option>--debug=object</option> feature not working when <command>scons</command> -is run with the python +is run with the Python <option>-O</option> option or from optimized Python (.pyo) modules.</para> @@ -2048,7 +2048,7 @@ env['BAR'] = 'bar' <para>As a convenience, construction variables may also be set or modified by the -<emphasis>parse_flags</emphasis> +<emphasis role="bold">parse_flags</emphasis> keyword argument, which applies the &f-link-env-MergeFlags; method (described below) to the argument value @@ -2228,7 +2228,7 @@ def exists(env): return True # in SConstruct: -env = Environment(tools = ['default', ('my_tool', {'arg1': 'abc'})], +env = Environment(tools=['default', ('my_tool', {'arg1': 'abc'})], toolpath=['tools']) </programlisting> @@ -2247,7 +2247,7 @@ With a nested tool name the dot represents a directory seperator</para> <programlisting> # namespaced builder -env = Environment(ENV = os.environ, tools = ['SubDir1.SubDir2.SomeTool']) +env = Environment(ENV=os.environ, tools=['SubDir1.SubDir2.SomeTool']) env.SomeTool(targets, sources) # Search Paths @@ -2293,75 +2293,104 @@ env.SomeTool(targets, sources) <refsect2 id='builder_methods'><title>Builder Methods</title> -<para>Build rules are specified by calling a construction -environment's builder methods. -The arguments to the builder methods are -<emphasis role="bold">target</emphasis> -(a list of targets to be built, -usually file names) +<para>You tell <program>scons</program> what to build +by calling Builders, functions which know to take a +particular action when given files of a particular type +to produce a particular result type. <program>scons</program> +defines a number of builders, and you can also write your own. +Builders are attached to a &consenv; as methods, +and the available builder methods are listed as +key-value pairs in the +<envar>BUILDERS</envar> attribute of the &consenv;. +The available builders can be displayed like this +for debugging purposes: +</para> + +<literallayout class="monospaced"> +print("Builders:", list(env['BUILDERS'])) +</literalllayout> + +<para> +Builder methods always take two arguments: +<replaceable>target</replaceable> +(a target or a list of targets to be built) and -<emphasis role="bold">source</emphasis> -(a list of sources to be built, -usually file names).</para> +<replaceable>source</replaceable> +(a source or list of sources to be used as input +when building), +although in some circumstances, +the target argument can actually be omitted (see below). +Builder methods also take a variety of +keyword arguments, described below. +</para> <para>Because long lists of file names can lead to a lot of quoting, <command>scons</command> -supplies a -<emphasis role="bold">Split()</emphasis> +supplies a &Split; global function and a same-named environment method that split a single string into a list, separated on strings of white-space characters. -(These are similar to the split() member function of Python strings -but work even if the input isn't a string.)</para> +(These are similar to the Python string <function>split</function> +method, but work even if the input isn't a string.)</para> -<para>Like all Python arguments, -the target and source arguments to a builder method -can be specified either with or without -the "target" and "source" keywords. -When the keywords are omitted, -the target is first, -followed by the source. -The following are equivalent examples of calling the Program builder method:</para> +<para> +The target and source arguments to a builder method +can be specified either as positional arguments, +in which case the target comes first, or as +keyword arguments, using <parameter>target=</parameter> +and <parameter>source=</parameter>. +The following are equivalent examples of calling the +&Program; builder method: +</para> <literallayout class="monospaced"> env.Program('bar', ['bar.c', 'foo.c']) env.Program('bar', Split('bar.c foo.c')) env.Program('bar', env.Split('bar.c foo.c')) -env.Program(source = ['bar.c', 'foo.c'], target = 'bar') -env.Program(target = 'bar', Split('bar.c foo.c')) -env.Program(target = 'bar', env.Split('bar.c foo.c')) -env.Program('bar', source = 'bar.c foo.c'.split()) +env.Program(source=['bar.c', 'foo.c'], target='bar') +env.Program(target='bar', source=Split('bar.c foo.c')) +env.Program(target='bar', source=env.Split('bar.c foo.c')) +env.Program('bar', source='bar.c foo.c'.split()) </literallayout> -<para>Target and source file names -that are not absolute path names -(that is, do not begin with -<emphasis role="bold">/</emphasis> -on POSIX systems -or -<emphasis role="bold">\</emphasis> -on Windows systems, -with or without -an optional drive letter) -are interpreted relative to the directory containing the -<emphasis role="bold">SConscript</emphasis> -file being read. -An initial -<emphasis role="bold">#</emphasis> -(hash mark) -on a path name means that the rest of the file name -is interpreted relative to -the directory containing -the top-level -<emphasis role="bold">SConstruct</emphasis> -file, -even if the -<emphasis role="bold">#</emphasis> -is followed by a directory separator character -(slash or backslash).</para> +<para> +Python follows the POSIX pathname convention for path +strings: if a string begins with the operating system pathname separator +(on Windows both the slash and backslash separator work, +and any leading drive specifier is ignored for +the determination) it is considered an absolute path, +otherwise it is a relative path. +If the path string contains no separator characters, +it is searched for as a file in the current directory. If it +contains separator characters, the search follows down +from the starting point, which is the top of the directory tree for +an absolute path and the current directory for a relative path. +</para> +<para> +<command>scons</command> recognizes a third way to specify +path strings: if the string begins with +the <emphasis role="bold">#</emphasis> character it is +top-relative - it works like a relative path but the +search follows down from the directory containing the top-level +<emphasis role="bold">SConstruct</emphasis> rather than +from the current directory (the # is allowed +to be followed by a pathname separator, which is ignored if +found in that position). +Top-relative paths only work in places where &scons; will +interpret the path (see some examples below). To be +used in other contexts the string will need to be converted +to a relative or absolute path first. +</para> + +<para> +Target and source pathnames can be absolute, relative, or +top-relative. Relative pathnames are searched considering the +directory of the <emphasis role="bold">SConscript</emphasis> +file currently being processed as the "current directory". +</para> <para>Examples:</para> @@ -2403,12 +2432,12 @@ executable program or <emphasis role="bold">bar.exe</emphasis> (on Windows systems) -from the bar.c source file:</para> +from the <filename>bar.c</filename> source file:</para> <literallayout class="monospaced"> -env.Program(target = 'bar', source = 'bar.c') -env.Program('bar', source = 'bar.c') -env.Program(source = 'bar.c') +env.Program(target='bar', source='bar.c') +env.Program('bar', source='bar.c') +env.Program(source='bar.c') env.Program('bar.c') </literallayout> @@ -2418,28 +2447,31 @@ keyword argument may be specified when calling a Builder. When specified, all source file strings that are not absolute paths +or top-relative paths will be interpreted relative to the specified <emphasis role="bold">srcdir</emphasis>. The following example will build the -<emphasis role="bold">build/prog</emphasis> +<filename>build/prog</filename> (or -<emphasis role="bold">build/prog.exe</emphasis> +<filename>build/prog.exe</filename> on Windows) program from the files -<emphasis role="bold">src/f1.c</emphasis> +<filename>src/f1.c</filename> and -<emphasis role="bold">src/f2.c</emphasis>:</para> +<filename>src/f2.c</filename>: +</para> <literallayout class="monospaced"> env.Program('build/prog', ['f1.c', 'f2.c'], srcdir='src') </literallayout> -<para>It is possible to override or add construction variables when calling a -builder method by passing additional keyword arguments. -These overridden or added -variables will only be in effect when building the target, so they will not -affect other parts of the build. For example, if you want to add additional -libraries for just one program:</para> +<para>It is possible to <emphasis>override</emphasis> (replace or add) +construction variables when calling a +builder method by passing them as keyword arguments. +These overrides +will only be in effect when building that target, and will not +affect other parts of the build. For example, if you want to specify +some libraries needed by just one program:</para> <literallayout class="monospaced"> env.Program('hello', 'hello.c', LIBS=['gl', 'glut']) @@ -2459,7 +2491,7 @@ for dependencies on the non-standard library names; see the descriptions of these variables, below, for more information.)</para> <para>It is also possible to use the -<emphasis>parse_flags</emphasis> +<emphasis role="bold">parse_flags</emphasis> keyword argument in an override, to merge command-line style arguments into the appropriate construction variables @@ -2504,8 +2536,7 @@ from SCons.Script import * </literallayout> <para>All builder methods return a list-like object -containing Nodes that -represent the target or targets that will be built. +containing Nodes that will be built. A <emphasis>Node</emphasis> is an internal SCons object @@ -2517,9 +2548,8 @@ can be passed to other builder methods as source(s) or passed to any SCons function or method where a filename would normally be accepted. For example, if it were necessary -to add a specific -<option>-D</option> -flag when compiling one specific object file:</para> +to add a specific preprocessor define +when compiling one specific object file:</para> <literallayout class="monospaced"> bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR') @@ -2530,14 +2560,14 @@ env.Program(source = ['foo.c', bar_obj_list, 'main.c']) makes for a more portable build by avoiding having to specify a platform-specific object suffix -when calling the Program() builder method.</para> +when calling the &Program; builder method.</para> -<para>Note that Builder calls will automatically "flatten" +<para>Note that builder calls will automatically "flatten" the source and target file lists, -so it's all right to have the bar_obj list -return by the StaticObject() call +so it's all right to have the <literal>bar_obj_list</literal> +returned by the &StaticObject; call in the middle of the source file list. -If you need to manipulate a list of lists returned by Builders +If you need to manipulate a list of lists returned by builders directly using Python, you can either build the list by hand:</para> @@ -2549,8 +2579,7 @@ for object in objects: print(str(object)) </literallayout> -<para>Or you can use the -<emphasis role="bold">Flatten</emphasis>() +<para>Or you can use the &Flatten; function supplied by scons to create a list containing just the Nodes, which may be more convenient:</para> @@ -2563,23 +2592,23 @@ for object in objects: print(str(object)) </literallayout> -<para>Note also that because Builder calls return +<para>Note also that because builder calls return a list-like object, not an actual Python list, you should <emphasis>not</emphasis> -use the Python -<emphasis role="bold">+=</emphasis> -operator to append Builder results to a Python list. +use the Python add +operator (<literal>+</literal> or <literal>+=</literal>) +to append builder results to a Python list. Because the list and the object are different types, Python will not update the original list in place, but will instead create a new Node-list object containing the concatenation of the list -elements and the Builder results. +elements and the builder results. This will cause problems for any other Python variables in your SCons configuration that still hold on to a reference to the original list. -Instead, use the Python -<markup>.extend()</markup> +Instead, use the Python list +<function>extend</function> method to make sure the list is updated in-place. Example:</para> @@ -2592,7 +2621,7 @@ object_files = [] # # It will not update the object_files list in place. # -# Instead, use the .extend() method: +# Instead, use the list extend method: object_files.extend(Object('bar.c')) </literallayout> @@ -2609,7 +2638,7 @@ print("The path to bar_obj is:", str(bar_obj_list[0])) <para>Note again that because the Builder call returns a list, we have to access the first element in the list -<emphasis role="bold">(bar_obj_list[0])</emphasis> +(<literal>(bar_obj_list[0])</literal>) to get at the Node that actually represents the object file.</para> @@ -2672,7 +2701,12 @@ to use just the filename portion of the targets and source.</para> <para><command>scons</command> -provides the following builder methods:</para> +predefined the following builder methods. +Depending on the setup of a particular +&consenv; and on the type and software +installation status of the underlying system, +not all builders may be available to that +&consenv;.</para> <!-- '\""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" --> <!-- '\" BEGIN GENERATED BUILDER DESCRIPTIONS --> @@ -4409,7 +4443,7 @@ functions return and <emphasis>Dir</emphasis> Nodes, respectively. -python objects, respectively. +Python objects, respectively. Those objects have several user-visible attributes and methods that are often useful:</para> @@ -5426,17 +5460,15 @@ a = Action(build_it, varlist=['XXX']) </programlisting> <para>The -<emphasis role="bold">Action</emphasis>() +&Action; global function can be passed the following optional keyword arguments to modify the Action object's behavior:</para> - -<para><emphasis role="bold">chdir</emphasis> -The -<emphasis role="bold">chdir</emphasis> -keyword argument specifies that +<para> +<replaceable>chdir</replaceable> +specifies that scons will execute the action after changing to the specified directory. If the @@ -5481,15 +5513,9 @@ a = Action("build < ${SOURCE.file} > ${TARGET.file}", chdir=1) </literallayout> - -<para><emphasis role="bold">exitstatfunc</emphasis> -The -<emphasis role="bold">Action</emphasis>() -global function -also takes an -<emphasis role="bold">exitstatfunc</emphasis> -keyword argument -which specifies a function +<para> +<replaceable>exitstatfunc</replaceable> +specifies a function that is passed the exit status (or return value) from the specified action @@ -5511,11 +5537,9 @@ a = Action("build < ${SOURCE.file} > ${TARGET.file}", </programlisting> -<para><emphasis role="bold">batch_key</emphasis> -The -<emphasis role="bold">batch_key</emphasis> -keyword argument can be used -to specify that the Action can create multiple target files +<para> +<replaceable>batch_key</replaceable> +specifies that the Action can create multiple target files by processing multiple independent source files simultaneously. (The canonical example is "batch compilation" of multiple object files @@ -5524,7 +5548,7 @@ to a single invocation of a compiler such as Microsoft's Visual C / C++ compiler.) If the <emphasis role="bold">batch_key</emphasis> -argument is any non-False, non-callable Python value, +argument evaluates True and is not a callable object, the configured Action object will cause <command>scons</command> to collect all targets built with the Action object @@ -5556,7 +5580,7 @@ will be used to identify different for batch building. A <emphasis role="bold">batch_key</emphasis> -function must take the following arguments:</para> +function must accept the following arguments:</para> <variablelist> <varlistentry> @@ -5688,7 +5712,7 @@ sequences of file manipulation without relying on platform-specific external commands: -that</para> +</para> <literallayout class="monospaced"> env = Environment(TMPBUILD = '/tmp/builddir') env.Command('foo.out', 'foo.in', @@ -5848,13 +5872,13 @@ env.Command('marker', 'input_file', <para>Before executing a command, <command>scons</command> -performs construction variable interpolation on the strings that make up -the command line of builders. -Variables are introduced by a -<emphasis role="bold">$</emphasis> +performs construction variable interpolation on the string that makes up +the command line of the builder. +Variables are introduced in such strings by a +<literal>$</literal> prefix. -Besides construction variables, scons provides the following -variables for each command execution:</para> +Besides regular construction variables, scons provides the following +special variables for each command execution:</para> <variablelist> <varlistentry> @@ -5923,15 +5947,19 @@ from sources that have <emphasis>not</emphasis> changed since the target was last built.</para> -<para>(Note that the above variables are reserved -and may not be set in a construction environment.)</para> - </listitem> </varlistentry> </variablelist> -<para>For example, given the construction variable CC='cc', targets=['foo'], and -sources=['foo.c', 'bar.c']:</para> +<para>Note that the above variables are reserved +and may not be set in a construction environment.</para> + +<para>For example, given the construction variables +<literal>CC='cc'</literal>, +<literal>targets=['foo']</literal> +and +<literal>sources=['foo.c', 'bar.c']</literal>: +</para> <literallayout class="monospaced"> action='$CC -c -o $TARGET $SOURCES' @@ -5944,7 +5972,8 @@ cc -c -o foo foo.c bar.c </literallayout> <para>Variable names may be surrounded by curly braces ({}) -to separate the name from the trailing characters. +to separate the name from surrounding characters which +are not part of the name. Within the curly braces, a variable name may have a Python slice subscript appended to select one or more items from a list. @@ -6107,20 +6136,42 @@ may be a callable Python function associated with a construction variable in the environment. The function should -take four arguments: -<emphasis>target</emphasis> -- a list of target nodes, -<emphasis>source</emphasis> -- a list of source nodes, -<emphasis>env</emphasis> -- the construction environment, -<emphasis>for_signature</emphasis> -- a Boolean value that specifies +accept four arguments: +</para> +<variablelist> + <varlistentry> + <term><replaceable>target</replaceable></term> + <listitem> +<para>a list of target nodes</para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable>source</replaceable></term> + <listitem> +<para>a list of source nodes</para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable>env</replaceable></term> + <listitem> +<para>the construction environment</para> + </listitem> + </varlistentry> + <varlistentry> + <term><replaceable>for_signature</replaceable></term> + <listitem> +<para>a Boolean value that specifies whether the function is being called -for generating a build signature. +for generating a build signature. </para> + </listitem> + </varlistentry> +</variablelist> + +<para> SCons will insert whatever the called function returns -into the expanded string:</para> +into the expanded string: +</para> <programlisting> def foo(target, source, env, for_signature): @@ -6201,9 +6252,10 @@ echo Last build occurred . > $TARGET <refsect2 id='python_code_substitution'><title>Python Code Substitution</title> -<para>Any python code within -<emphasis role="bold">${</emphasis>-<emphasis role="bold">}</emphasis> -pairs gets evaluated by python 'eval', with the python globals set to +<para>Any Python code within +curly braces (and introduced by the variable prefix <literal>$</literal>) +gets evaluated by the Python <function>eval</function> statement, +with the Python globals set to the current environment's set of construction variables. So in the following case:</para> <literallayout class="monospaced"> @@ -6219,14 +6271,20 @@ echo FOO > foo.out <literallayout class="monospaced"> echo BAR > foo.out </literallayout> -<para>according to the current value of env['COND'] when the command is -executed. The evaluation occurs when the target is being -built, not when the SConscript is being read. So if env['COND'] is changed +<para>according to the current value of <literal>env['COND']</literal> +when the command is executed. +The evaluation takes place when the target is being +built, not when the SConscript is being read. So if +<literal>env['COND']</literal> is changed later in the SConscript, the final value will be used.</para> -<para>Here's a more interesting example. Note that all of COND, FOO, and -BAR are environment variables, and their values are substituted into -the final command. FOO is a list, so its elements are interpolated +<para>Here's a more interesting example. Note that all of +<envar>COND</envar>, +<envar>FOO</envar>, +and +<envar>BAR</envar> are construction variables, +and their values are substituted into the final command. +<envar>FOO</envar> is a list, so its elements are interpolated separated by spaces.</para> <literallayout class="monospaced"> @@ -6574,9 +6632,10 @@ do this, in part, by sharing an ability to interpret UNIX-like path names. For example, the Cygwin tools will internally translate a Cygwin path name -like /cygdrive/c/mydir +like <filename>/cygdrive/c/mydir</filename> to an equivalent Windows pathname -of C:/mydir (equivalent to C:\mydir).</para> +of <filename>C:/mydir</filename> (equivalent to <filename>C:\mydir</filename>). +</para> <para>Versions of Python that are built for native Windows execution, @@ -6584,7 +6643,8 @@ such as the python.org and ActiveState versions, do not have the Cygwin path name semantics. This means that using a native Windows version of Python to build compiled programs using Cygwin tools -(such as gcc, bison, and flex) +(such as <command>gcc</command>, <command>bison</command>, +and <command>flex</command>) may yield unpredictable results. "Mixing and matching" in this way can be made to work, |