Avoid this Realloc Anti-pattern! It Can Leak Memory.

foo = realloc(foo, ...);

ret = realloc(foo, ...);
if (ret == NULL) {
    // [...] handle error
    free(foo);
    return ENOMEM;
}
foo = ret;

Avoid the anti-pattern foo = realloc(foo, ...);. On failure, realloc returns NULL, but leaves the original buffer untouched. So this anti pattern risks losing the reference to the original buffer, causing a memory leak.