把过程前景 [英] Bring process to foreground

问题描述

我已经exec'd由后台进程的处理（其中读取和写入到终端类型）。我可以用ps看到它。
试图将其带到前台，这是我尝试：

I have a process (which reads and writes to terminal type) that has been exec'd by a background process. I can see it using ps. Trying to bring it to foreground, this is what I attempted:

int main()

{

    FILE* fd = popen("pidof my_program","r");

    // ...
    // Some code to get the pid of my_program as mpid
    //...

    printf("pid of my_program is %d",mpid);
    signal(SIGTTOU, SIG_IGN);
    setpgid(mpid,0); // Set program group id to pid of process
    tcsetpgrp(0,mpid); // Give it terminal stdin access
    tcsetpgrp(1,mpid); // Give it terminal stdout access
    return 0;
}

它不工作，虽然。有人可以帮助我在这？
谢谢你。

It isn't working though. Can someone help me on this? Thanks.

推荐答案

您可以做到这一点软的方式，通过调用shell命令 FG 并传递给它的PID（谏）。

You could do it the "soft" way, by calling the shell command fg and pass it the pid (adviced).

如果您想code吧，这是FG / BG如何为coded进入庆典（不要不要不要）：

If you want to code it, this is how fg/bg is coded into bash (don't don't don't):

static int
fg_bg (list, foreground)
     WORD_LIST *list;
     int foreground;
{
  sigset_t set, oset;
  int job, status, old_async_pid;
  JOB *j;

  BLOCK_CHILD (set, oset);
  job = get_job_spec (list);

  if (INVALID_JOB (job))
    {
      if (job != DUP_JOB)
    sh_badjob (list ? list->word->word : _("current"));

      goto failure;
    }

  j = get_job_by_jid (job);
  /* Or if j->pgrp == shell_pgrp. */
  if (IS_JOBCONTROL (job) == 0)
    {
      builtin_error (_("job %d started without job control"), job + 1);
      goto failure;
    }

  if (foreground == 0)
    {
      old_async_pid = last_asynchronous_pid;
      last_asynchronous_pid = j->pgrp;  /* As per Posix.2 5.4.2 */
    }

  status = start_job (job, foreground);

  if (status >= 0)
    {
    /* win: */
      UNBLOCK_CHILD (oset);
      return (foreground ? status : EXECUTION_SUCCESS);
    }
  else
    {
      if (foreground == 0)
    last_asynchronous_pid = old_async_pid;

    failure:
      UNBLOCK_CHILD (oset);
      return (EXECUTION_FAILURE);
    }
}

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