Converts a string to a long integer.
#include <stdlib.h>
long strtol (
const char *ptr,
char **endptr,
int base);
(IN) Points to the string to be converted.
(OUT) Points to the first unrecognized character.
(IN) Specifies the number base to use.
If successful, returns the converted value. Otherwise, returns one of the following:
If the correct value would cause overflow, returns LONG_MAX or LONG_MIN according to the sign and sets errno to ERANGE.
If base is out of range, returns 0 and sets errno to EINVAL.
If the input string cannot be converted, returns 0 and sets errno to EINVAL.
The strtol function converts the string pointed to by ptr to an object of type long int. The function recognizes a string containing:
Optional whitespace characters
An optional plus (+) or minus (-) sign
A sequence of digits and letters
The conversion ends at the first unrecognized character. A pointer to that character is stored in the object to which endptr points if endptr is not NULL.
The base parameter must have a value between 2 and 36. The letters a through z and A through Z represent the values 10 through 35. Only those letters whose designated values are less than base are permitted. If the value of base is 16, the characters 0x or 0X can optionally precede the sequence of letters and digits.