Even when using the VariantDir function, it is more natural to use it with a subsidiary SConscript file, because then you don't have to adjust your individual build instructions to use the variant directory path. For example, if the src/SConscript looks like this:

env = Environment()
env.Program('hello.c')
      

Then our SConstruct file could look like:

VariantDir('build', 'src')
SConscript('build/SConscript')
      

Yielding the following output:

% ls src
SConscript  hello.c
% scons -Q
cc -o build/hello.o -c build/hello.c
cc -o build/hello build/hello.o
% ls build
SConscript  hello  hello.c  hello.o

This is completely equivalent to the use of SConscript with the variant_dir argument from earlier in this chapter, but did require callng the SConscript using the already established variant directory path to trigger that behavior. If you call SConscript('src/SConscript') you would get a normal in-place build in src.