Description

   The atoi and atol functions convert the initial portion of a
   string to its decimal int or long int value, respectively. The
   atoi and atol functions do not account for overflows resulting
   from the conversion. The string to be converted has the following
   format:

   [white-spaces][+|-]digits

   The function call atol (str) is equivalent to strtol (str,
   (char**)NULL, 10), and the function call atoi (str) is equivalent
   to (int) strtol (str, (char**)NULL, 10), except, in both cases,
   for the behavior on error.