#include "reallocarray.h"

#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
void *reallocarray(void *optr, size_t nmemb, size_t size) {
    if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
        nmemb > 0 && SIZE_MAX / nmemb < size) {
        errno = ENOMEM;
        return NULL;
    }
    return realloc(optr, size * nmemb);
}