Is NULL always false?

Question

Is it safe to assume that NULL always translates to false in C?

void *somePtr = NULL;

if (!somePtr) {
  /* This will always be executed? */
}
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Answer 1

Yes, mostly.

First off, NULL is a typedef. I could royally screw you over by saying in a previously included header

#define NULL 1

This might not make a lot of sense, but since when has other people's code ever made sense? :)

Also, while it's probably syntactically safe, it's not semantically correct. NULL means "nothing", neither true or false or a boolean value or int or string. It means "a symbol for nothing". So testing for NULL is more like a philisophical issue: If a tree falls in the forest, and if(listener), does it make a sound?

Do everyone a favor and be clear about testing against NULL.