.\" Copyright (c) 2001, 2002 Steven Knight .\" .\" Permission is hereby granted, free of charge, to any person obtaining .\" a copy of this software and associated documentation files (the .\" "Software"), to deal in the Software without restriction, including .\" without limitation the rights to use, copy, modify, merge, publish, .\" distribute, sublicense, and/or sell copies of the Software, and to .\" permit persons to whom the Software is furnished to do so, subject to .\" the following conditions: .\" .\" The above copyright notice and this permission notice shall be included .\" in all copies or substantial portions of the Software. .\" .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY .\" KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE .\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND .\" NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE .\" LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION .\" OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION .\" WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. .\" .\" __FILE__ __REVISION__ __DATE__ __DEVELOPER__ .\" .\" ES - Example Start - indents and turns off line fill .de ES .RS .nf .. .\" EE - Example End - ends intend and turns line fill back on .de EE .RE .fi .. .TH SCONS 1 "January 2002" .SH NAME scons \- software constructor .SH SYNOPSIS .B scons [ .IR options ... ] [ .IR name = val ... ] [ .IR targets ... ] .SH DESCRIPTION The .B scons utility builds software (or other files) by determining which component pieces must be rebuilt and executing the necessary commands to rebuild them. By default, .B scons searches for a file named .IR SConstruct , .IR Sconstruct , or .I sconstruct (in that order) in the current directory and reads its configuration from the first file found. An alternate file name may be specified via the .B -f option. If the specified file is not in the local directory, .B scons will internally change its working directory (chdir) to the directory containing the file. The configuration file specifies the files to be built, and (optionally) the rules to build those files. Reasonable default rules exist for building common software components (executable programs, object files, libraries), so that for simple software projects, only the target and input files need be specified. .B scons can scan known input files automatically for dependency information (for example, #include statements in C or C++ files) and will rebuild dependent files appropriately whenever any "included" input file changes. .B scons supports the ability to define new scanners for unknown input file types. .B scons is normally executed in a top-level directory containing a .I SConstruct file, specifying the target or targets to be built as command-line arguments. The command .ES scons . .EE will build all target files in or below the current directory .RI ( . ")." .ES scons / .EE will build all target files in or below the root directory (i.e., all files). Specific targets may be supplied: .ES scons foo bar .EE Targets may be omitted from the command line, in which case the targets specified in the configuration file(s) as .B Default targets will be built: .ES scons .EE Specifying "cleanup" targets in configuration files is not necessary. The .B -c flag removes all files necessary to build the specified target: .ES scons -c . .EE to remove all target files, or: .ES scons -c build export .EE to remove target files under build and export. A subset of a hierarchical tree may be built by remaining at the top-level directory (where the .I SConstruct file lives) and specifying the subdirectory as the target to be built: .ES scons src/subdir .EE or by changing directory and invoking scons with the .B -u option, which traverses up the directory hierarchy until it finds the .I SConstruct file, and then builds targets relatively to the current subdirectory: .ES cd src/subdir scons -u . .EE .B scons supports building multiple targets in parallel via a .B -j option that takes, as its argument, the number of simultaneous tasks that may be spawned: .ES scons -j 4 .EE builds four targets in parallel, for example. Values of variables to be passed to the configuration file(s) may be specified on the command line: .ES scons debug=1 . .EE These variables can be used in the configuration file(s) to modify the build in any way. .\" .B scons .\" can maintain a cache of target (derived) files that can .\" be shared between multiple builds. When caching is enabled in a .\" configuration file, any target files built by .\" .B scons .\" will be copied .\" to the cache. If an up-to-date target file is found in the cache, it .\" will be retrieved from the cache instead of being rebuilt locally. .\" Caching behavior may be disabled and controlled in other ways by the .\" .BR --cache-force , .\" .BR --cache-disable , .\" and .\" .B --cache-show .\" command-line options. The .\" .B --random .\" option is useful whenever multiple builds may be .\" trying to update the cache simultaneously. .B scons requires Python version 1.5.2 or later. There should be no other dependencies or requirements to run .B scons. The default .B scons configuration assumes use of the Microsoft Visual C++ compiler suite on WIN32 systems, and assumes a C compiler named .B cc and a C++ compiler named .B c++ (such as found in the GNU C compiler suite) on any other type of system. You may, of course, override these default values by appropriate configuration of Environment construction variables. .SH OPTIONS In general, .B scons supports the same command-line options as GNU .BR make , and many of those supported by .BR cons . .TP -b Ignored for compatibility with non-GNU versions of .BR make. .TP -c, --clean, --remove Clean up by removing all target files for which a construction command is specified. .\" .TP .\" --cache-disable, --no-cache .\" Disable caching. Will neither retrieve files from cache nor flush .\" files to cache. Has no effect if use of caching is not specified .\" in a configuration file. .\" .\" .TP .\" --cache-force, --cache-populate .\" Populate a cache by forcing any already-existing up-to-date .\" target files to the cache, in addition to files built by this .\" invocation. This is useful to populate a new cache with .\" appropriate target files, or to make available in the cache .\" any target files recently built with caching disabled via the .\" .B --cache-disable .\" option. .\" .\" .TP .\" --cache-show .\" When retrieving a target file from a cache, show the command .\" that would have been executed to build the file. This produces .\" consistent output for build logs, regardless of whether a target .\" file was rebuilt or retrieved from cache. .TP .RI "-C" " directory" ", --directory=" directory Change to the specified .I directory before searching for the .IR SConstruct , .IR Sconstruct , or .I sconstruct file, or doing anything else. Multiple .B -C options are interpreted relative to the previous one, and the right-most .B -C option wins. (This option is nearly equivalent to .BR "-f directory/SConstruct" , except that it will search for .IR SConstruct , .IR Sconstruct , or .I sconstruct in the specified directory.) .\" .TP .\" -d .\" Display dependencies while building target files. Useful for .\" figuring out why a specific file is being rebuilt, as well as .\" general debugging of the build process. .TP .RI --debug= type Debug the build process. .I type specifies what type of debugging: .TP .RI --debug=pdb Re-run SCons under the control of the .RI pdb Python debugger. The .RI --debug=pdb argument will be stripped from the command-line, but all other arguments will be passed in-order to the SCons invocation run by the debugger. .TP .RI --debug=tree Print the dependency tree after each top-level target is built. .TP -e, --environment-overrides Variables from the execution environment override construction variables from the configuration files. .TP .RI -f " file" ", --file=" file ", --makefile=" file ", --sconstruct=" file Use .I file as the initial configuration file. If .I file is in another directory, .B scons will change to that directory before building targets. .TP -h, --help Print a local help message for this build, if one is defined in the configuration file(s), plus a line that describes the .B -H option for command-line option help. If no local help message is defined, prints the standard help message about command-line options. Exits after displaying the appropriate message. .TP -H, --help-options Print the standard help message about command-line options and exit. .TP -i, --ignore-errors Ignore all errors from commands executed to rebuild files. .TP .RI -I " directory" ", --include-dir=" directory Specifies a .I directory to search for imported Python modules. If several .B -I options are used, the directories are searched in the order specified. .TP .RI -j " N" ", --jobs=" N Specifies the number of jobs (commands) to run simultaneously. If there is more than one .B -j option, the last one is effective. .\" ??? If the .\" .B -j .\" option .\" is specified without an argument, .\" .B scons .\" will not limit the number of .\" simultaneous jobs. .TP -k, --keep-going Continue as much as possible after an error. The target that failed and those that depend on it will not be remade, but other targets specified on the command line will still be processed. .\" .TP .\" .RI -l " N" ", --load-average=" N ", --max-load=" N .\" No new jobs (commands) will be started if .\" there are other jobs running and the system load .\" average is at least .\" .I N .\" (a floating-point number). .\" .\" .TP .\" --list-derived .\" List derived files (targets, dependencies) that would be built, .\" but do not build them. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .\" .\" .TP .\" --list-actions .\" List derived files that would be built, with the actions .\" (commands) that build them. Does not build the files. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .\" .\" .TP .\" --list-where .\" List derived files that would be built, plus where the file is .\" defined (file name and line number). Does not build the files. .\" [XXX This can probably go away with the right .\" combination of other options. Revisit this issue.] .TP -m Ignored for compatibility with non-GNU versions of .BR make . .TP -n, --just-print, --dry-run, --recon No execute. Print the commands that would be executed to build any out-of-date target files, but do not execute the commands. .\" .TP .\" .RI -o " file" ", --old-file=" file ", --assume-old=" file .\" Do not rebuild .\" .IR file , .\" and do .\" not rebuild anything due to changes in the contents of .\" .IR file . .\" .TP .\" .RI --override " file" .\" Read values to override specific build environment variables .\" from the specified .\" .IR file . .\" .TP .\" -p .\" Print the data base (construction environments, .\" Builder and Scanner objects) that are defined .\" after reading the configuration files. .\" After printing, a normal build is performed .\" as usual, as specified by other command-line options. .\" This also prints version information .\" printed by the .\" .B -v .\" option. .\" .\" To print the database without performing a build do: .\" .\" .ES .\" scons -p -q .\" .EE .TP .RI --profile= file Run SCons under the Python profile and save the results in the specified .IR file . The results may be analyzed using the Python pstats module. .TP -q, --question Do not run any commands, or print anything. Just return an exit status that is zero if the specified targets are already up to date, non-zero otherwise. .\" .TP .\" -r, -R, --no-builtin-rules, --no-builtin-variables .\" Clear the default construction variables. Construction .\" environments that are created will be completely empty. .\" .\" .TP .\" --random .\" Build dependencies in a random order. This is useful when .\" building multiple trees simultaneously with caching enabled as a .\" way to prevent multiple builds from simultaneously trying to build .\" or retrieve the same target files. .TP -s, --silent, --quiet Silent. Do not print commands that are executed to rebuild target files. .TP -S, --no-keep-going, --stop Ignored for compatibility with GNU .BR make . .TP -t, --touch Ignored for compatibility with GNU .BR make . (Touching a file to make it appear up-to-date is unnecessary when using .BR scons .) .TP -u, --up, --search-up Walks up the directory structure until an .I SConstruct , .I Sconstruct or .I sconstruct file is found, and uses that as the top of the directory tree. Only targets at or below the current directory will be built. .TP -U Works exactly the same way as the .B -u option except for the way default targets are handled. When this option is used and no targets are specified on the command line, all default targets are built, whether or not they are below the current directory. .TP -v, --version Print the .B scons version, copyright information, list of authors, and any other relevant information. Then exit. .TP -w, --print-directory Print a message containing the working directory before and after other processing. .TP --no-print-directory Turn off -w, even if it was turned on implicitly. .\" .TP .\" .RI --write-filenames= file .\" Write all filenames considered into .\" .IR file . .\" .\" .TP .\" .RI -W " file" ", --what-if=" file ", --new-file=" file ", --assume-new=" file .\" Pretend that the target .\" .I file .\" has been .\" modified. When used with the .\" .B -n .\" option, this .\" show you what would be rebuilt if you were to modify that file. .\" Without .\" .B -n .\" ... what? XXX .\" .\" .TP .\" --warn-undefined-variables .\" Warn when an undefined variable is referenced. .\" .\" .TP .\" .RI -Y " repository" ", --repository=" repository .\" Search the specified repository for any input and target .\" files not found in the local directory hierarchy. Multiple .\" .B -Y .\" options may specified, in which case the .\" repositories are searched in the order specified. .SH CONFIGURATION FILE REFERENCE .SS Construction Environments A construction environment is the basic means by which the configuration files communicate build information to .BR scons . A new construction environment is created using the .B Environment function: .ES env = Environment() .EE Build rules are specified by calling builder methods on a construction environment. The arguments to the builder methods are target (a list of target files) and source (a list of source files). If a string is given for target or source, then .B scons interprets it as a space delimited list of files. The following are examples of calling a builder: .ES env.Program(target = 'bar', source = 'bar.c foo.c') env.Program('bar', 'bar.c foo.c') env.Program('bar', ['bar.c', 'foo.c']) .EE .B scons provides the following builders: .IP Object Builds an object file from one or more C/C++ source files. Source files must have one of the following extensions: .c, .C, .cc, .cpp, .cxx, .c++, .C++. The target object file prefix and suffix (if any) are automatically added. Example: .ES env.Object(target = 'bar', source = 'bar.c') .EE .IP Program Builds an executable given one or more object files or C/C++ source files. If any C/C++ source files are given, then they will be automatically compiled to object files. The executable prefix and suffix (if any) are automatically added to the target. Example: .ES env.Program(target = 'bar', source = 'bar.c foo.o') .EE .IP Library Builds a library given one or more object files or C/C++ source files. If any C/C++ source files are given, then they will be automatically compiled to object files. The library prefix and suffix (if any) are automatically added to the target. Example: .ES env.Library(target = 'bar', source = 'bar.c foo.o') .EE .IP CFile Builds a C source file given a lex (.l) or yacc (.y) input file. The suffix specified by the $CFILESUFFIX construction variable (.c by default) is automatically added to the target if it is not already present. Example: .ES env.CFile(target = 'foo.c', source = 'foo.l') # builds foo.c env.CFile(target = 'bar', source = 'bar.y') # builds bar.c .EE .IP CXXFile Builds a C++ source file given a lex (.ll) or yacc (.yy) input file. The suffix specified by the $CXXFILESUFFIX construction variable (.cc by default) is automatically added to the target if it is not already present. Example: .ES env.CXXFile(target = 'foo.cc', source = 'foo.ll') # builds foo.cc env.CXXFile(target = 'bar', source = 'bar.yy') # builds bar.cc .EE .IP DVI Builds a .dvi file from a .tex, .ltx or .latex input file. The suffix specified by the $DVISUFFIX construction variable (.dvi by default) is automatically added to the target if it is not already present. Example: .ES env.DVI(target = 'aaa.dvi', source = 'aaa.tex') # builds from aaa.tex env.DVI(target = 'bbb', source = 'bbb.ltx') # builds bbb.dvi env.DVI(target = 'ccc.dvi', source = 'ccc.latex') # builds from ccc.latex .EE .LP C/C++ source files are automatically scanned for dependencies by .B scons so the dependencies do not need to be provided. In addition, all builder targets automatically depend on their sources. An explicit dependency can be specified using the .B Depends method of a construction environment (see below). Additional Environment methods include: .TP .RI Command( target ", " source ", " commands ) Executes a specific command (or list of commands) to build a target file or files. This is more convenient than defining a separate Builder object for a single special-case build. .ES env.Command('foo.out', 'foo.in', "$FOO_BUILD < $SOURCES > $TARGET") env.Command('bar.out', 'bar.in', ["rm -f $TARGET", "$BAR_BUILD < $SOURCES > $TARGET"]) .EE .TP .RI Copy([ 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. .ES env2 = env.Copy() env3 = env.Copy(CCFLAGS = '-g') .EE .TP .RI Depends( target ", " dependency ) Specifies an explicit dependency; the target file(s) will be rebuilt whenever the dependency file(s) has changed. This should only be necessary for cases where the dependency is not caught by a Scanner for the file. .ES env.Depends('foo', 'other-input-file-for-foo') .EE .TP .RI 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. .ES dict = env.Dictionary() cc_dict = env.Dictionary('CC', 'CCFLAGS', 'CCCOM') .EE .TP .RI Ignore( target ", " dependency ) The specified dependency file(s) will be ignored when deciding if the target file(s) need to be rebuilt. .ES env.Ignore('foo', 'foo.c') env.Ignore('bar', ['bar1.h', 'bar2.h']) .EE .TP .RI Install( dir ", " source ) Installs one or more files in a destination directory. The file names remain the same. .ES env.Install(dir = '/usr/local/bin', source = 'foo bar') .EE .TP .RI InstallAs( target ", " source ) Installs one or more files as specific file names, allowing changing a file name as part of the installation. It is an error if the target and source list different numbers of files. .ES env.InstallAs(target = '/usr/local/bin/foo', source = 'foo_debug') env.InstallAs(target = '../lib/libfoo.a ../lib/libbar.a', source = 'libFOO.a libBAR.a') .EE .TP .RI 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 Alias( alias ", " targets ) Creates a phony target that expands to one or more other targets. 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. .ES env.Alias('install', ['/usr/local/bin', '/usr/local/lib']) .EE .TP .RI Update( key = val ", [...])" Updates the contents of an environment with the specified keyword arguments. .ES env.Update(CCFLAGS = '-g', FOO = 'foo.xxx') .EE .SS Construction Variables A construction environment has an associated dictionary of construction variables that are used by built-in or user-supplied build rules. A number of useful construction variables are automatically defined by scons for each supported platform, and additional construction variables can be defined by the user. The following is a list of the automatically defined construction variables: .IP AR The static library archiver. .IP ARFLAGS General options passed to the static library archiver. .IP ARCOM The command line used to generate a static library from object files. .IP BUILDERS A list of the available builders. [Alias, CFile, CXXFile, DVI, Library, Object, Program] by default. .IP CC The C compiler. .IP CCFLAGS General options that are passed to the C compiler. .IP CCCOM The command line used to compile a C source file to an object file. .IP CFILESUFFIX The suffix for C source files. This is used by the internal CFile builder when generating C files from Lex (.l) or YACC (.y) input files. The default suffix, of course, is .IR .c . .IP CPPPATH The list of directories that the C preprocessor will search for include directories. The C/C++ implicit dependency scanner will search these directories for include files. Don't explicitly put include directory arguments in CCFLAGS or CXXFLAGS because the result will be non-portable and the directories will not be searched by the dependency scanner. Note: directory names in CPPPATH will be looked-up relative to the SConscript directory when they are used in a command. To force .B scons to look-up a directory relative to the root of the source tree use #: .ES env = Environment(CPPPATH='#/include') .EE .IP The directory look-up can also be forced using the .BR Dir () function: .ES include = Dir('include') env = Environment(CPPPATH=include) .EE .IP CXX The C++ compiler. .IP CXXFILESUFFIX The suffix for C++ source files. This is used by the internal CXXFile builder when generating C++ files from Lex (.ll) or YACC (.yy) input files. The default suffix is .IR .cc . .IP CXXFLAGS General options that are passed to the C++ compiler. .IP CXXCOM The command line used to compile a C++ source file to an object file. .IP ENV A dictionary of environment variables to use when invoking commands. Note that, by default, .B scons does .I not propagate the environment in force when you execute .B scons to the commands used to build target files. This is so that builds will be guaranteed repeatable regardless of the environment variables set at the time .B scons is invoked. If you want to propagate your environment variables to the commands executed to build target files, you must do so explicitly: .ES import os env = Environment(ENV = os.environ) .EE .RS Note that you can choose only to propagate certain environment variables. A common example is the system .B PATH environment variable, so that .B scons uses the same utilities as the invoking shell (or other process): .RE .ES import os env = Environment(ENV = {'PATH' : os.environ['PATH']}) .EE .IP INCPREFIX The prefix used to specify an include directory on the C compiler command line. .IP INCSUFFIX The suffix used to specify an include directory on the C compiler command line. .IP LEX The lexical analyzer generator. .IP LEXFLAGS General options passed to the lexical analyzer generator. .IP LEXCOM The command line used to call the lexical analyzer generator to generate a source file. .IP LIBDIRPREFIX The prefix used to specify a library directory on the linker command line. .IP LIBDIRSUFFIX The suffix used to specify a library directory on the linker command line. .IP LIBLINKPREFIX The prefix used to specify a library to link on the linker command line. .IP LIBLINKSUFFIX The suffix used to specify a library to link on the linker command line. .IP LIBPATH The list of directories that will be searched for libraries. The implicit dependency scanner will search these directories for include files. Don't explicitly put include directory arguments in LINKFLAGS because the result will be non-portable and the directories will not be searched by the dependency scanner. Note: directory names in LIBPATH will be looked-up relative to the SConscript directory when they are used in a command. To force .B scons to look-up a directory relative to the root of the source tree use #: .ES env = Environment(LIBPATH='#/libs') .EE .IP The directory look-up can also be forced using the .BR Dir () function: .ES libs = Dir('libs') env = Environment(LIBPATH=libs) .EE .IP LIBPREFIX The prefix used for library file names. .IP LIBS A list of one or more libraries that will be linked with any executable programs created by this environment. .IP LIBSUFFIX The suffix used for library file names. .IP LINK The linker. .IP LINKFLAGS General options passed to the linker. .IP LINKCOM The command line used to link object files into an executable. .IP OBJPREFIX The prefix used for object file names. .IP OBJSUFFIX The suffix used for object file names. .IP PROGPREFIX The prefix used for executable file names. .IP PROGSUFFIX The suffix used for executable file names. .IP RANLIB The archive indexer. .IP RANLIBFLAGS General options passed to the archive indexer. .IP SCANNERS A list of the available implicit dependency scanners. [CScan] by default. .IP YACC The parser generator. .IP YACCFLAGS General options passed to the parser generator. .IP YACCCOM The command line used to call the parser generator to generate a source file. .LP Construction variables can be retrieved and set using the .B Dictionary method of the construction environment: .ES dict = env.Dictionary() dict["CC"] = "cc" .EE or using the [] operator: .ES env["CC"] = "cc" .EE Construction variables can also be passed to the construction environment constructor: .ES env = Environment(CC="cc") .EE or when copying a construction environment using the .B Copy method: .ES env2 = env.Copy(CC="cl.exe") .EE .SS Other Functions .B scons also provides various additional functions, not associated with a construction environment, that configuration files can use: .TP .RI BuildDir( build_dir ", " src_dir ", [" duplicate ]) This specifies a build directory to use for all derived files. .I build_dir specifies the build directory to be used for all derived files that would normally be built under .IR src_dir . Multiple build directories can be set up for multiple build variants, for example. .B scons will link or copy (depending on the platform) all the source files into the build directory if .I duplicate is set to 1 (the default). If .I duplicate is set to 0, then .B scons will not copy or link any source files, which may cause build problems in certain situations (e.g. C source files that are generated by the build). .IR duplicate =0 is usually safe, and is always more efficient than .IR duplicate =1. .TP .RI Default( targets ) This specifies a list of default targets. Default targets will be built by .B scons if no explicit targets are given on the command line. Multiple targets can be specified either as a space delimited string of target file names or as separate arguments. Target names with white space may be be enclosed in an array to prevent the string from being split into separate file names. .BR Default () will also accept the return value of any of the construction environment builder methods. Example: .ES Default('foo', 'bar', 'baz', ['file with whitespace']) .EE .TP .RI Dir( name ", [" directory ]) This returns an object that represents a given 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. .TP .RI Export( vars ) This tells .B scons to export a list of variables from the current configuration file to all other configuration files. The exported variables are kept in a global collection, so subsequent exports will over-write previous exports that have the same name. Multiple variable names can be passed to .BR Export () in a space delimited string or as seperate arguments. Example: .ES Export("env") .EE .TP .RI File( name ", [" directory ]) This returns an object that represents a given 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. .TP .RI Help( text ) This specifies help text to be printed if the .B -h argument is given to .BR scons . .B scons will exit after printing out the help text. .TP .RI Import( vars ) This tells .B scons to import a list of variables into the current configuration 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 () in a space delimited string or as seperate arguments. Example: .ES Import("env") .EE .TP .RI Return( vars ) This tells .B scons what variable(s) to use as the return value(s) of the current configuration file. These variables will be returned to the "calling" configuration file as the return value(s) of .BR SConscript (). Multiple variable names can be passed to .BR Return () in a space delimited string or as seperate arguments. Example: .ES Return("foo") .EE .TP .RI SConscript( script ", [" exports ]) This tells .B scons to execute .I script as a configuration file. The optional .I exports argument provides a list of variable names to export to .IR script ". " exports can also be a space delimited string of variables names. .I script must use the .BR Import () function to import the variables. Any variables returned by .I script using .BR Return () will be returned by the call to .BR SConscript (). Examples: .ES SConscript('dir/SConscript') foo = SConscript('subdir/SConscript', "env") .EE .TP .RI SetCommandHandler( function ) This registers a user .I function as the handler for interpreting and executing command-line strings. The function must expect three arguments: .ES def commandhandler(cmd, args, env): .EE .I cmd is the path to the command to be executed. .I args is that arguments to the command. .I env is a dictionary of the environment variables in which the command should be executed. .TP .RI WhereIs( program ", [" path ", [" pathext ]]) 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, or the user's current PATH (os.environ['PATH']) by default. On Win32 systems, searches for executable programs with any of the file extensions listed in the specified .I pathext, or the user's current PATHEXT (os.environ['PATHEXT']) by default. .SH EXTENDING SCONS .SS Builder Objects .B scons can be extended by adding new builders to a construction environment using the .B Builder function. Builder accepts the following arguments: .IP name The name of the builder. This will be the name of the construction environment method used to create an instance of the builder. .IP action The command line string used to build the target from the source. .B action can also be a dictionary mapping source file name suffixes to any combination of command line strings (if the builder should accept multiple source file extensions), Python functions, or Action objects (see the next section). .IP prefix The prefix that will be prepended to the target file name. .IP suffix The suffix that will be appended to the target file name. .IP src_suffix The expected source file name suffix. .IP src_builder Specifies a builder to use when a source file name suffix does not match any of the suffixes of the builder. Using this argument produces a multi-stage builder. .IP generator A function that returns a list of command lines that will be executed to build the target(s) from the source(s). The command lines must be returned as lists, where the first element of the list is the executable, and the other elements in the list are the arguments that will be passed to the executable. The .I generator and .I action arguments must not both be used for the same Builder. The generator function should take 3 arguments: .I source - a list of source nodes, .I target - a list of target nodes, .I env - the construction environment. Example: .ES def g(env, source, target): return [["gcc", "-c", "-o"] + target + source] b = Builder(name="Object", generator=g) .EE .SS Action Objects The Builder function will turn its .B action keyword argument into an appropriate internal Action object. Occasionally, it may be more efficient to create an explicit Action object and use it to initialize multiple Builder objects, rather than let each separate Builder object create a separate Action. The Action method takes a single argument and returns an appropriate object for the action represented by the type of the argument: .IP Action If the argument is already an Action object, the object is simply returned. .IP String If the argument is a string, a command-line Action is returned. .ES Action('$CC -c -o $TARGET $SOURCES') .EE .IP Function If the argument is a Python function, a function Action is returned. The Python function takes three keyword arguments, .B target (a Node object representing the target file), .B source (a Node object representing the source file) and .BR env (the construction environment used for building the target file). The .B target and .B source arguments may be lists of Node objects if there is more than one target file or source file. The actual target and source file name(s) may be retrieved from their Node objects via the built-in Python str() function: .ES target_file_name = str(target) source_file_names = map(lambda x: str(x), source) .EE .IP The function should return .B 0 or .B None to indicate a successful build of the target file(s). The function may raise an exception or return a non-zero exit status to indicate an unsuccessful build. .ES def build_it(target = None, source = None, env = None): # build the target from the source return 0 a = Action(build_it) .EE .IP List If the argument is a list, then a list of Action objects is returned. An Action object is created as necessary for each element in the list. .PP If the action argument is not one of the above, None is returned. .SS Variable Substitution Before executing a command, .B scons performs construction variable interpolation on the strings that make up the command line of builders. Variables are introduced by a .B $ prefix. Besides construction variables, scons provides the following variables for each command execution: .IP TARGET The file name of the target being built, or the file name of the first target if multiple targets are being built. .IP TARGETS The file names of all targets being built. .IP SOURCES The file names of the sources of the build command. .LP For example, given the construction variable CC='cc', targets=['foo'], and sources=['foo.c', 'bar.c']: .ES action='$CC -c -o $TARGET $SOURCES' .EE would produce the command line: .ES cc -c -o foo foo.c bar.c .EE Variable names may be surrounded by curly braces ({}) to separate the name from the trailing characters. Within the curly braces, a variable name may have a Python slice subscript appended to select one or more items from a list. In the previous example, the string: .ES ${SOURCES[1]} .EE would produce: .ES bar.c .EE Additionally, a variable name may have the following special modifiers appended within the enclosing curly braces to modify the interpolated string: .IP base The base path of the file name, including the directory path but excluding any suffix. .IP dir The name of the directory in which the file exists. .IP file The file name, minus any directory portion. .IP filebase Just the basename of the file, minus any suffix and minus the directory. .IP suffix Just the file suffix. .LP For example, the specified target will expand as follows for the corresponding modifiers: .ES $TARGET => sub/dir/file.x ${TARGET.base} => sub/dir/file ${TARGET.dir} => sub/dir ${TARGET.file} => file.x ${TARGET.filebase} => file ${TARGET.suffix} => .x .EE .LP The special pseudo-variables .R $( and .R $) may be used to surround parts of a command line that may change .I without causing a rebuild--that is, which are not included in the signature of target files built with this command. All text between .R $( and .R $) will be removed from the command line before it is added to file signatures, and the .R $( and .R $) will be removed before the command is executed. For example, the command line: .ES echo Last build occurred $( $TODAY $). > $TARGET .EE .LP would execute the command: .ES echo Last build occurred $TODAY. > $TARGET .EE .LP but the command signature added to any target files would be: .ES echo Last build occurred . > $TARGET .EE .SS Scanner Objects You can use the .B Scanner function to define objects to scan new file types for implicit dependencies. Scanner accepts the following arguments: .IP name The name of the Scanner. This is mainly used to identify the Scanner internally. .IP argument An optional argument that, if specified, will be passed to the scanner function. .IP skeys An optional list that can be used to determine which scanner should be used for a given Node. In the usual case of scanning for file names, this array can be a list of suffixes for the different file types that this Scanner knows how to scan. .IP function A Python function that will process the Node (file) and return a list of strings (file names) representing the implicit dependencies found in the contents. The function takes three arguments: def scanner_function(node, env, arg): The .B node argument is the internal SCons node representing the file. Use .B str(node) to fetch the name of the file, and .B node.get_contents() to fetch contents of the file. The .B env argument is the construction environment for the scan. Fetch values from it using the .B env.Dictionary() method. The .B arg argument is the argument supplied when the scanner was created. .SH EXAMPLES To help you get started using SCons, here is a brief overview of some common tasks: .SS Basic Compilation From a Single Source File .ES env = Environment() env.Program(target = 'foo', source = 'foo.c') .EE .SS Basic Compilation From Multiple Source Files .ES env = Environment() env.Program(target = 'foo', source = 'f1.c f2.c f3.c') .EE .SS Setting a Compilation Flag .ES env = Environment(CCFLAGS = '-g') env.Program(target = 'foo', source = 'foo.c') .EE .SS Search The Local Directory For .h Files Note: You do .I not need to specify -I options by hand. SCons will construct the right -I options from CPPPATH. .ES env = Environment(CPPPATH = ['.']) env.Program(target = 'foo', source = 'foo.c') .EE .SS Search Multiple Directories For .h Files .ES env = Environment(CPPPATH = ['include1', 'include2']) env.Program(target = 'foo', source = 'foo.c') .EE .SS Building a Library .ES env = Environment() env.Library(target = 'mylib', source = 'l1.c l2.c') .EE .SS Linking a Local Library Into a Program .ES env = Environment(LIBS = 'mylib', LIBPATH = ['.']) env.Library(target = 'mylib', source = 'l1.c l2.c') env.Program(target = 'prog', source = 'p1.c p2.c') .EE .SS Defining Your Own Builder Object You .I must specify a "name" keyword argument for the builder, as that becomes the Environment method name you use to call the builder. Notice also that you can leave off the target file suffix, and the builder will add it automatically. .ES bld = Builder(name = 'PDFBuilder', action = 'pdftex < $SOURCES > $TARGET' suffix = '.pdf', src_suffix = '.tex') env = Environment(BUILDERS = [bld]) env.PDFBuilder(target = 'foo.pdf', source = 'foo.tex') # The following creates "bar.pdf" from "bar.tex" env.PDFBuilder(target = 'bar', source = 'bar') .EE .SS Defining Your Own Scanner Object .ES import re include_re = re.compile(r'^include\\s+(\\S+)$', re.M) def kfile_scan(node, env, arg): contents = node.get_contents() includes = include_re.findall(contents) return includes kscan = Scanner(name = 'kfile', function = kfile_scan, argument = None, skeys = ['.k']) scanners = Environment().Dictionary('SCANNERS') env = Environment(SCANNERS = scanners + [kscan]) env.Command('foo', 'foo.k', 'kprocess < $SOURCES > $TARGET') bar_in = File('bar.in') env.Command('bar', bar_in, 'kprocess $SOURCES > $TARGET') bar_in.scanner_set(kscan) .EE .SS Creating a Hierarchical Build Notice that the file names specified in a subdirectory are relative to that subdirectory. .ES SConstruct: env = Environment() env.Program(target = 'foo', source = 'foo.c') SConscript('sub/SConscript') sub/SConscript: env = Environment() # Builds sub/foo from sub/foo.c env.Program(target = 'foo', source = 'foo.c') SConscript('dir/SConscript') sub/dir/SConscript: env = Environment() # Builds sub/dir/foo from sub/dir/foo.c env.Program(target = 'foo', source = 'foo.c') .EE .SS Sharing Variables Between SConscript Files You must explicitly Export() and Import() variables that you want to share between SConscript files. .ES SConstruct: env = Environment() env.Program(target = 'foo', source = 'foo.c') Export("env") SConscript('subdirectory/SConscript') subdirectory/SConscript: Import("env") env.Program(target = 'foo', source = 'foo.c') .EE .SS Building Multiple Variants From the Same Source Use the BuildDir() method to establish one or more separate build directories for a given source directory, then use the SConscript() method to specify the SConscript files in the build directories: .ES SConstruct: ccflags = '-DFOO' Export("ccflags") BuildDir('foo', 'src') SConscript('foo/SConscript') ccflags = '-DBAR' Export("ccflags") BuildDir('bar', 'src') SConscript('bar/SConscript') src/SConscript: Import("ccflags") env = Environment(CCFLAGS = ccflags) env.Program(target = 'src', source = 'src.c') .EE Note the use of the Export() method to set the "ccflags" variable to a different value for each variant build. .SH ENVIRONMENT .IP SCONS_LIB_DIR Specifies the directory that contains the SCons Python module directory (e.g. /home/aroach/scons-src-0.01/src/engine). .IP SCONSFLAGS A string of options that will be used by scons in addition to those passed on the command line. .SH "SEE ALSO" .B scons User Manual, .B scons Design Document, .B scons source code. .SH AUTHORS Steven Knight .br Anthony Roach