malloc() crashing on Windows but not on Mac

Question

The following code:

#include<stdlib.h>
#include<stdio.h>

int main (void) {
    FILE** f;
    if ( (*f = (FILE *)malloc( sizeof(FILE *)) ) == NULL) {
        printf("Out of RAM or some other disaster!\n");
        return 1;
    }
    printf("OK!\n");
    return 0;
}

compiles and runs without complaint on Mac OS X 10.8. However on Windows 7 (compiling with MinGW) it crashes on the malloc(). Why would this be and or any ideas to stop it happening?

Thanks!

Note: This was obviously originally part of a larger program but I've reduced the entire program to the above and tried just this code on both the Mac and PC and have replicated the behaviour.

Answer 1

f is not pointing anywhere yet, so dereferencing it (*f) is invalid and has an undefined behavior.

Answer 2

You're assigning the malloc-ed memory to *f which is undefined behavior, since f is uninitialized. Change to

f = (FILE **)malloc( sizeof(FILE *))