Secure countof()
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#include <stdio.h>
#include <assert.h>
#define countof(a) (assert((void *)(a) == (void *)&(a)), sizeof(a) / sizeof(*(a)))
int main(void)
{
int a[20] = {0};
int *b = a;
int count_a = countof(a);
//int count_b = countof(b); // fails
// Passing a function will give incorrect answer. But I find that to be an unlikely mistake.
int count_main = countof(main);
printf("Array count: %i\n", count_a);
printf("Function: %i // failure.\n", count_main);
return 0;
}
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