test2.c

来自「这个是学习嵌入式开发的重要例子」· C语言 代码 · 共 112 行

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>

void signal_handler(int s);
static int check_set(sigset_t * set, int s);
static int check_all(sigset_t * set);

int main(int argc, char **argv)
{
  sigset_t out_set;

  // XXX: step 1, define a new sigset
  sigset_t in_set;

#if 0
  fprintf(stdout, "SIG_BLOCK = %d\n", SIG_BLOCK);
  fprintf(stdout, "SIG_SETMASK = %d\n", SIG_SETMASK);
  fprSIG_BLOCKintf(stdout, "SIG_UNBLOCK = %d\n", SIG_UNBLOCK);
#endif

  // XXX: step 2, empty the new sigset
  // int sigfillset(sigset_t *set);
  sigemptyset(&in_set);
  //check_set(&out_set, SIGINT);

  // XXX: step 3, add SIGINT to new sigset
  //int sigaddset(sigset_t *set, int signo);
  sigaddset(&in_set, SIGINT);
  sigaddset(&in_set, SIGTERM);

  // XXX: step 4, update original sigset
  sigprocmask(SIG_BLOCK, &in_set, &out_set);

  // XXX: step 5, the original sigset is stored in out_set

  check_set(&out_set, SIGINT);
  check_set(&out_set, SIGTERM);
  check_all(&out_set);

  //int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
  if (sigprocmask(0, NULL, &out_set) < 0)
  {
    fprintf(stderr, "call sigprocmask() failed: %s\n", strerror(errno));
    exit(1);
  }

  check_set(&out_set, SIGINT);
  check_all(&out_set);

  for (;;)
  {
  }

  exit(0);

  if (sigismember(&out_set, SIGINT))
  {
    fprintf(stdout, "SIGINT handler is set.\n");
  }
  else
  {
    fprintf(stdout, "SIGINT handler is not set.\n");
  }

  return 0;
}

static int check_set(sigset_t * set, int s)
{
  int result;

  //return sigismember(set, s);
  if ((result = sigismember(set, s)))
  {
    fprintf(stdout, "signal %d is in set.\n", s);
  }
  else
  {
    fprintf(stdout, "signal %d is not in set.\n", s);
  }

  return result;
}

static int check_all(sigset_t * set)
{
  int i;
  int result;

  for (i = 0; i < 32; i++)
  {
    if ((result = sigismember(set, i)))
    {
      fprintf(stdout, "[%s:%d:%s]signal %d is in set.\n", __FILE__, __LINE__, __func__, i);
    }
    else
    {
      fprintf(stdout, "[%s:%d:%s]signal %d is not in set.\n", __FILE__, __LINE__, __func__, i);
    }
  }

  return result;
}

void signal_handler(int s)
{
}