If I define
#if SOMETHING
#endif
and I have not defined SOMETHING anywhere. Would the code inside #if compile ?
If I define #if SOMETHING #endif and I have not defined SOMETHING anywhere. Would
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If I define
#if SOMETHING
#endif
and I have not defined SOMETHING anywhere. Would the code inside #if compile ?
When the name used in the argument expression of
#ifis not defined as a macro (after all other macro replacement is finished), it is replaced with0. This means that your#if SOMETHINGwill be interpreted as#if 0. The code under#ifwill be removed by preprocessor.The rule applies to more complex expressions as well. You can do
which will evaluate to
#if 42, since unknown nameBis interpreted as0