difference between if and #if

[sarathius]

what is the difference between if and #if. when to use what?

thanks in advance

[matsp]

#if is done before the compiler sees the code, so it has to be a constant known before you even start compiling the code. This is typically selecting different variants of the same code (e.g. #if WINDOWS ... #elsif LINUX ... #else ... ).

if is done during the runtime of the application, so it can do "anything" [although if you write something like if(x) and the compiler can know FOR SURE that x will always be non-zero, it may of course skip the test of x, and always execute the code anyways].

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Mats