How do I tell if the c function atoi failed or if it was a string of zeros?

Question

When using the function atoi (or strtol or similar functions for that matter), how can you tell if the integer conversion failed or if the C-string

Answer 1

It's been a while since I've done and C/C++, but it would appear to me that the (overly) simple solution would be to check just the string for "0".

int value = atoi(string_number.c_str());

if ( !value && string_number != "0" ) {
  // error
} else {
  // great success!
}