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Index > Macroinstructions > #ifndef problem

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afw2004



Joined: 16 Jun 2005
Posts: 49
Location: Kharkov, Ukraine
afw2004 30 Jun 2005, 15:00
How can I check if symbol is defined in FASM? (like #ifndef in C++)
Post 30 Jun 2005, 15:00
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland
Tomasz Grysztar 30 Jun 2005, 15:10
For the label or numerical constant (which are defined at assembly stage) it would be:
Code:
if defined symbol
 ; ...
end if    

This operator checks whether the symbol is defined anywhere in source (with prediction), not only whether it was defined earlier. Read part 4 of this article for more details about this specific problem.

For the symbolic constant (defined with EQU, processed at preprocessing stage), it can be something like this example from the manual:
Code:
match =TRUE, DEBUG { include 'debug.inc' }    

to check for specific value; or something like this:
Code:
match =DEBUG, DEBUG { }    

to check whether DEBUG constant was not defined at all.
Post 30 Jun 2005, 15:10
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