atol() - convert ASCII string to long integer
#include <stdlib.h>
long atol (const char *nptr)
The atol(3) function converts the initial portion of the string pointed to by nptr to long integer representation.
It is equivalent to:
strtol(nptr, (char **)NULL, 10);
atof(3)
atoi(3)
strtod(3)
strtol(3)
strtoul(3)