Input validation of an Integer using atoi()
atoi is not suitable for error checking. Use strtol or strtoul instead.
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
long int result;
char *pend;
errno = 0;
result = strtol (buffer, &pend, 10);
if (result == LONG_MIN && errno != 0)
{
/* Underflow. */
}
if (result == LONG_MAX && errno != 0)
{
/* Overflow. */
}
if (*pend != '\0')
{
/* Integer followed by some stuff (floating-point number for instance). */
}