sending a struct to a function

Quote:

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Originally Posted by draft c99

The free function causes the space pointed to by ptr to be deallocated, that is, made
available for further allocation. If ptr is a null pointer, no action occurs. Otherwise, if
the argument does not match a pointer earlier returned by the calloc, malloc,or
realloc function, or if the space has been deallocated by a call to free or realloc,
the behavior is undefined.

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So long as your compiler is sporting a nice shiny "ANSI" badge, then all should be well.

> Or should I assume that anyone have new compiler?
That depends how much effort you want to put into it. Some code goes out of it's way to be compatible with as many things as possible, but it can look horrible if managed poorly.

Unless there is a need (or anticipation) to run your code on pre-ANSI C, then freeing NULL will be the least of your problems. The biggie to fix would be that pre-ANSI C doesn't understand function prototypes.

Edit: I see dwks already mentioned C89 :)