C strtol() function

C strtol() function - Convert a string to a long integer

Syntax strtol() function

long int strtol(const char *str, char **endptr, int base)

The strtol() function is used to convert a character string to a long integer value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0. The parameter str points to a sequence of characters that can be interpreted as a numeric value of type long int.

Parameters strtol() function

Return value from strtol()

• Upon successful completion, the function returns the converted value.
• Returns 0 if no conversion is possible.

Example: strtol() function

The following example shows the usage of strtol() function.

#include <stdlib.h>
#include <stdio.h>
 
int main(void)
{
   char *string, *stopstring;
   long result;
   int bs;
 
   string = "2334567765924932";
   printf("String = %s\n", string);
   for (bs = 2; bs <= 8; bs *= 2)
   {
      result = strtol(string, &stopstring, bs);
      printf("\nstrtol = %ld (base %d)\n", result, bs);
      printf("Stopped scan at %s\n", stopstring);
      }
}

Output:

String = 2334567765924932

strtol = 0 (base 2)
Stopped scan at 2334567765924932

strtol = 47 (base 4)
Stopped scan at 4567765924932

strtol = 326299637 (base 8)
Stopped scan at 924932

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