test11.c

这个是学习嵌入式开发的重要例子

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

void process_signal(int sig);
void child_process_main(void);

int main(int argc, char **argv)
{
  int status;

  fprintf(stdout, "SIGCHLD = %d\n", SIGCHLD);
  fprintf(stdout, "SIGTERM = %d\n", SIGTERM);

  // void (*signal(int sig, void (*func)(int)))(int);
  signal(SIGCHLD, process_signal);
  //signal(SIGTERM, process_signal);
  //signal(SIGINT, process_signal);
  //signal(7, process_signal);
  //signal(SIGCHLD, process_signal);

  //sleep(1000);

  pid_t pid;

  if ((pid = fork()) < 0)
  {
    fprintf(stderr, "fork() failed: %s\n", strerror(errno));
    return 1;
  }
  else if (pid == 0)
  {
    child_process_main();
    exit(0);
  }
  else
  {
    // parent process, continue
  }

#if 0
  pid_t returned_pid;

  returned_pid = wait(&status);

  fprintf(stdout, "returned_pid = %d, error: %s\n", returned_pid, strerror(errno));
#endif

  sleep(1000);

  return 0;
}

void child_process_main(void)
{
  sleep(1);
  fprintf(stdout, "I'm child process, pid = %d\n", getpid());
}

void process_signal(int sig)
{
  printf("Catched %d signal.\n", sig);

  int status;

  if (sig == SIGCHLD)
  {
    pid_t returned_pid;

    returned_pid = wait(&status);

    fprintf(stdout, "%d process is exited.\n", returned_pid);
  }
}