Linux定时器

使用linux定时器可以定时的处理一些事务或者定时的发出一些信号,如SIGALRM,SIGINT,SIGQUIT等信号。

linux定时器的代码
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#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>

#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); } while (0)

static void sig_handler(int sig, siginfo_t *si, void *uc)
{
  printf("Caught signal %d\n", sig);
}

int   main(int argc, char *argv[])
{
  timer_t timerid;
  struct sigevent sev;
  struct itimerspec its;
  sigset_t newMask, oldMask;
  struct sigaction sa;

  sa.sa_flags = SA_SIGINFO;
  sa.sa_sigaction = sig_handler;
  sigemptyset(&sa.sa_mask);
  if (sigaction(SIGINT, &sa, NULL) == -1)
  {
     errExit("sigaction");
  }

  sigemptyset(&newMask);
  sigaddset(&newMask, SIGINT);
  if (sigprocmask(SIG_BLOCK, &newMask, &oldMask) == -1)
  {
     errExit("sigprocmask");
  }

  sev.sigev_notify = SIGEV_SIGNAL;
  sev.sigev_signo = SIGINT;
  sev.sigev_value.sival_ptr = &timerid;
  if (timer_create(CLOCK_REALTIME, &sev, &timerid) == -1)
  {
     errExit("timer_create");
  }

  its.it_value.tv_sec = 1;
  its.it_value.tv_nsec = 0;
  its.it_interval.tv_sec = its.it_value.tv_sec;
  its.it_interval.tv_nsec = its.it_value.tv_nsec;

  if (timer_settime(timerid, 0, &its, NULL) == -1)
  {
      errExit("timer_settime");
  }

  if (sigprocmask(SIG_SETMASK, &oldMask, NULL) == -1)
  {
     errExit("sigprocmask");
  }
  while(1)
  {
      sleep(10);
  }
  return 0;
}

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