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

Specifies the exceptions that will be ignored when expanding &consvars;. By default, any &consvar; 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 ignored exceptions. Calling it with no arguments means no exceptions will be ignored. 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 evaluate to ''. AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)