char *do_replace_cntrl_chars(char *str, char c) {
	if (str) {
		size_t i;
		for (i = 0; str[i]; i++) {
			if (iscntrl((unsigned char) str[i]))
				str[i] = c;
		}
	}
	return str;
}
char *do_replace_cntrl_chars(char *str, char c) {
	if (str) {
		size_t i;
		for (i = 0; str[i]; i++) {
			if (iscntrl((unsigned char) str[i]))
				str[i] = c;
		}
	}
	return str;
}