%scons; %builders-mod; %functions-mod; %tools-mod; %variables-mod; ]> ([exception, ...])

Specifies the exceptions that will be allowed when expanding construction variables. By default, any construction variable expansions that generate a NameError or IndexError exception will expand to a '' (an empty string) and not cause scons to fail. All exceptions not in the specified list will generate an error message and terminate processing. If &f-AllowSubstExceptions; is called multiple times, each call completely overwrites the previous list of allowed exceptions. Example: # Requires that all construction variable names exist. # (You may wish to do this if you want to enforce strictly # that all construction variables must be defined before use.) AllowSubstExceptions() # Also allow a string containing a zero-division expansion # like '${1 / 0}' to evalute to ''. AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)