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diff --git a/doc/user/variants.xml b/doc/user/variants.xml new file mode 100644 index 0000000..016202a --- /dev/null +++ b/doc/user/variants.xml @@ -0,0 +1,146 @@ +<!-- + + Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 The SCons Foundation + + 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. + +--> + +<!-- + +=head1 Variant builds + +=head2 Variations on a theme + +Other variations of this model are possible. For example, you might decide +that you want to separate out your include files into platform dependent and +platform independent files. In this case, you'd have to define an +alternative to C<$INCLUDE> for platform-dependent files. Most F<Conscript> +files, generating purely platform-independent include files, would not have +to change. + +You might also want to be able to compile your whole system with debugging +or profiling, for example, enabled. You could do this with appropriate +command line options, such as C<DEBUG=on>. This would then be translated +into the appropriate platform-specific requirements to enable debugging +(this might include turning off optimization, for example). You could +optionally vary the name space for these different types of systems, but, as +we'll see in the next section, it's not B<essential> to do this, since Cons +is pretty smart about rebuilding things when you change options. + +--> + + <para> + + The &variant_dir; keyword argument of + the &SConscript; function provides everything + we need to show how easy it is to create + variant builds using &SCons;. + Suppose, for example, that we want to + build a program for both Windows and Linux platforms, + but that we want to build it in a shared directory + with separate side-by-side build directories + for the Windows and Linux versions of the program. + + </para> + + <programlisting> + platform = ARGUMENTS.get('OS', Platform()) + + include = "#export/$PLATFORM/include" + lib = "#export/$PLATFORM/lib" + bin = "#export/$PLATFORM/bin" + + env = Environment(PLATFORM = platform, + BINDIR = bin, + INCDIR = include, + LIBDIR = lib, + CPPPATH = [include], + LIBPATH = [lib], + LIBS = 'world') + + Export('env') + + env.SConscript('src/SConscript', variant_dir='build/$PLATFORM') + </programlisting> + + <para> + + This SConstruct file, + when run on a Linux system, yields: + + </para> + + <screen> + % <userinput>scons -Q OS=linux</userinput> + Install file: "build/linux/world/world.h" as "export/linux/include/world.h" + cc -o build/linux/hello/hello.o -c -Iexport/linux/include build/linux/hello/hello.c + cc -o build/linux/world/world.o -c -Iexport/linux/include build/linux/world/world.c + ar rc build/linux/world/libworld.a build/linux/world/world.o + ranlib build/linux/world/libworld.a + Install file: "build/linux/world/libworld.a" as "export/linux/lib/libworld.a" + cc -o build/linux/hello/hello build/linux/hello/hello.o -Lexport/linux/lib -lworld + Install file: "build/linux/hello/hello" as "export/linux/bin/hello" + </screen> + + <para> + + The same SConstruct file on Windows would build: + + </para> + + <screen> + C:\><userinput>scons -Q OS=windows</userinput> + + scons: warning: No installed VCs + File "<stdin>", line 67, in __call__ + + scons: warning: No version of Visual Studio compiler found - C/C++ compilers most likely not set correctly + File "<stdin>", line 67, in __call__ + + scons: warning: No installed VCs + File "<stdin>", line 67, in __call__ + + scons: warning: No version of Visual Studio compiler found - C/C++ compilers most likely not set correctly + File "<stdin>", line 67, in __call__ + Install file: "build/windows/world/world.h" as "export/windows/include/world.h" + cl /Fobuild\windows\hello\hello.obj /c build\windows\hello\hello.c /nologo /Iexport\windows\include + cl /Fobuild\windows\world\world.obj /c build\windows\world\world.c /nologo /Iexport\windows\include + lib /nologo /OUT:build\windows\world\world.lib build\windows\world\world.obj + Install file: "build/windows/world/world.lib" as "export/windows/lib/world.lib" + link /nologo /OUT:build\windows\hello\hello.exe /LIBPATH:export\windows\lib world.lib build\windows\hello\hello.obj + Install file: "build/windows/hello/hello.exe" as "export/windows/bin/hello.exe" + </screen> + + <!-- + + <scons_example name="ex_var2"> + <file name="SConstruct" printme="1"> + env = Environment(OS = ARGUMENTS.get('OS')) + for os in ['newell', 'post']: + SConscript('src/SConscript', variant_dir='build/' + os) + </file> + </scons_example> + + <scons_output example="ex_var2"> + <scons_output_command>scons -Q</scons_output_command> + </scons_output> + + --> |