3.9. Overriding construction variables when calling a Builder

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:

env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])

or generate a shared library with a non-standard suffix:

env.SharedLibrary('word', 'word.cpp',

It is also possible to use the parse_flags keyword argument in an override to merge command-line style arguments into the appropriate construction variables (see env.MergeFlags).

This example adds 'include' to $CPPPATH, 'EBUG' to $CPPDEFINES, and 'm' to $LIBS.

env = Program('hello', 'hello.c', parse_flags='-Iinclude -DEBUG -lm')

Within the call to the builder action the environment is not cloned, instead an OverrideEnvironment() is created which is more light weight than a whole Environment()