function qt_wince_bsearch() throws an exception (Access violation) if doesn't find a key value

void *qt_wince_bsearch(const void *key,
           const void *base,
           size_t num,
           size_t size,
           int (__cdecl *compare)(const void *, const void *))
{
    size_t low = 0;
    size_t high = num - 1;
    while (low <= high) {
        unsigned int mid = ((unsigned) (low + high)) >> 1;
        int c = compare(key, (char*)base + mid * size);
        if (c < 0)
            high = mid - 1; // <-- high is an unsigned value, so if mid == 0 then high == 0xffffffff , and condition low <= high is not satisfied 
        else if (c > 0)
            low = mid + 1;
        else
            return (char*) base + mid * size;
    }
    return (NULL);
}