Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <errno.h>
       #include <limits.h>

       /* This test calls wcstoul() to convert a string to an     */
       /* unsigned long integer. wcstoul outputs the resulting    */
       /* integer and any characters that could not be converted. */

       #define MAX_STRING 128

       main()
       {

           int base = 10,
               errno;
           char *input_string = "1234.56";
           wchar_t string_array[MAX_STRING],
                  *ptr;
           size_t size;
           unsigned long int val;
           printf("base = [%d]\n", base);
           printf("String to convert = %s\n", input_string);
         if ((size = mbstowcs(string_array, input_string, MAX_STRING)) ==

               (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }
           printf("wchar_t string is = [%S]\n", string_array);

           errno = 0;
           val = wcstoul(string_array, &ptr, base);
           if (errno == 0) {
       printf("returned unsigned long int from wcstoul = [%u]\n", val);
             printf("wide char terminating scan(ptr) = [%S]\n\n", ptr);
           }
           if (errno == ERANGE) {
               perror("error value is :");
               printf("ULONG_MAX = [%u]\n", ULONG_MAX);
               printf("wcstoul failed, val = [%d]\n\n", val);
           }

       }

   Running the example program produces the following result:

   base = [10]
   String to convert = 1234.56
   wchar_t string is = [1234.56]
   returned unsigned long int from wcstoul = [1234]
   wide char terminating scan(ptr) = [.56]