A C++ `ltoa` function

void ltoa(const long value, char* buffer, const unsigned base) {
    bool negative = value < 0;
    long tmp = negative? -value: value;
    int i = 0;
    if (negative) { buffer[0] = '-'; i++; }
    do { tmp /= (long) base; i++; } while (tmp);
    buffer[i + 1] = '\0';
    tmp = negative? -value: value;
    do { buffer[--i] = "0123456789abcdef"[tmp % (long) base]; tmp /= (long) base; } while (tmp && i);
}