GDL Preprocessor Conditional Directives

GDL preprocessor conditional directives define conditional constructs. Each conditional construct begins with the #Ifdef directive and is terminated by the #Endif directive. In between, the #Elseifdef directive might appear zero, one, or more times. The optional #Else directive must appear between the last #Elseifdef directive (if any used) and the final #Endif directive.

Each of these directives partition the intervening data (non-preprocessor directives) into conditional sections; each section is preserved for the next stage of parsing or deleted during preprocessing as described below. Data that is not to be processed and that is not contained within any conditional constructs is always preserved.

Conditional section directives can be nested. The entire conditional construct from the #Ifdef to the closing #Endif must reside entirely within one section of the enclosing conditional construct.

GDL uses the following conditional directives:

#Ifdef

#Elseifdef

#Else

#Endif