test5.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 <unistd.h>
#include <string.h>
#include <errno.h>

void child_process_main(void);

int main(int argc, char **argv)
{
  fprintf(stdout, "[%d]current pid = %d, ppid = %d\n", getpid(), getpid(), getppid());

  int i;

  for (i = 0; i < 3; i++)
  {
    pid_t pid;

    //if ((pid = fork()) < 0)
    if ((pid = vfork()) < 0)
    {
      fprintf(stderr, "[%d]fork() failed: %s\n", getpid(), strerror(errno));
    }
    else if (pid == 0)
    {
      // XXX: Child process
      fprintf(stdout, "[%d]I'm new created process, pid = %d, ppid = %d\n", getpid(), getpid(), getppid());
      //child_process_main();
      //exec("ls");
      exit(0);
    }
    else
    {
      // XXX: parent process
      fprintf(stdout, "[%d] New created child process pid = %d\n", getpid(), pid);
      fprintf(stdout, "[%d] current pid = %d, ppid = %d\n", getpid(), getpid(), getppid());
    }
  }

  return 0;
}

void child_process_main(void)
{
  fprintf(stdout, "child_process_main()\n");
  //exit(0);
}