关于setitimer

#include <stdio.h>    // for printf()  
#include <unistd.h>   // for pause()  
#include <signal.h>   // for signal()  
#include <string.h>   // for memset()  
#include <sys/time.h> // struct itimeral. setitimer()  
void printMsg(int);  
int main() {  
    printf("in main\n");

  // Get system call result to determine successful or failed  
  int res = 0;  
  // Register printMsg to SIGALRM  
  signal(SIGALRM, printMsg);  
  struct itimerval tick;  
  // Initialize struct  
  memset(&tick, 0, sizeof(tick));  
  // Timeout to run function first time  
  tick.it_value.tv_sec = 0;  // sec  
  tick.it_value.tv_usec = 10000; // micro sec.  
  // Interval time to run function  
  tick.it_interval.tv_sec = 0;  
  tick.it_interval.tv_usec = 10000;  
  // Set timer, ITIMER_REAL : real-time to decrease timer,  
  //                          send SIGALRM when timeout  
  res = setitimer(ITIMER_REAL, &tick, NULL);  
  if (res) {  
    printf("Set timer failed!!/n"); 
  }  
  // Always sleep to catch SIGALRM signal  
  while(1) {  
     pause();  
  }  
  return 0;    
}  
void printMsg(int num) { 
  static int num1 = 0; 
  printf("%s, num1: %d\n","Hello World!!  num ", ++num1);  
}  

http://www.cnblogs.com/anywei/archive/2011/11/28/setitimer.html