Variant Builds
The build_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.
platform = ARGUMENTS.get('OS', Platform())
include = "#export/$PLATFORM/include"
lib = "#export/$PLATFORM/lib"
bin = "#export/$PLATFORM/bin"
env = Environment(PLATFORM = platform,
BINDIR = bin,
INCDIR = include,
LIBDIR = lib,
CPPPATH = [include],
LIBPATH = [lib],
LIBS = 'world')
Export('env')
env.SConscript('src/SConscript', build_dir='build/$PLATFORM')
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This SConstruct file,
when run on a Linux system, yields:
% scons -Q OS=linux
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"
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The same SConstruct file on Windows would build:
C:\>scons -Q OS=windows
Install file: "build/windows/world/world.h" as "export/windows/include/world.h"
cl /nologo /Iexport\windows\include /c build\windows\hello\hello.c /Fobuild\windows\hello\hello.obj
cl /nologo /Iexport\windows\include /c build\windows\world\world.c /Fobuild\windows\world\world.obj
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"
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