int concatenate(char * s, unsigned max_size, const char * s2) {
    unsigned int size;
    for(size = 0; s[size] != 0; ++size);

    for(unsigned int i = 0; size + i < max_size; ++i) {
	s[size + i] = s2[i];
	if (s2[i] == 0)
	    return 1;
    }
    s[max_size - 1] = 0;
    return 0;
}