test7.c

华清远见应用培训班例程源码

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

void signal_child_handler(int sig);

int main(int argc, char **argv)
{
  pid_t pid;

  if ((pid = fork()) < 0)
  {
    fprintf(stderr, "ERROR: Call fork() failed: %s, errno = %d.\n", strerror(errno), errno);
    exit(1);
  }

  if (pid > 0)
  {
    // XXX: Parent process

    fprintf(stdout, "[%d] I'm parent process.\n", getpid());
    fprintf(stdout, "[%d] New created process is %d.\n", getpid(), pid);

    signal(SIGCHLD, signal_child_handler);

    /*
       int status;
       pid_t p;
       //p = wait(&status);
       // pid_t waitpid(pid_t pid, int *status, int options);
       p = waitpid(pid, &status, 0);
       //wait(&status);

       fprintf(stdout, "[%d] DEBUG: catched process %d, status = %d.\n", getpid(), p, status);
     */

    for (;;)
    {
      sleep(1);
    }
  }
  else
  {
    // XXX: Child process
    fprintf(stdout, "[%d] I'm child process process, my pid is %d.\n", getpid(), getpid());

    sleep(5);
    exit(0);
  }

  return 0;
}

void signal_child_handler(int sig)
{
  int status;
  pid_t p;

  fprintf(stdout, "[%d]DEBUG: Cached SIGCHLD.\n", getpid());

  //p = waitpid(pid, &status, 0);
  wait(&status);
  fprintf(stdout, "[%d] DEBUG: catched process %d, status = %d.\n", getpid(), p, status);
}