C语言传递无符号长指针

#include <stdio.h>
#include <time.h>

void getSeconds(unsigned long *par);

int main () {

   unsigned long sec;
   getSeconds( &sec );

   /* print the actual value */
   printf("Number of seconds: %ld/n", sec );

   return 0;
}

void getSeconds(unsigned long *par) {
   /* get the current number of seconds */
   *par = time( NULL );
   return;
}