A way of test out GIO Subprocess if it's running/finished

Platform
1

Hello,
cannot find out if there’s some flag in GSubprocess structure that indicates the state of subprocess (running/finished), or some correspondent function to test out if a subprocess is still running or finished. I suppose it has to be something obvious that I’ve missed from its doc. Can you please give some hints on this topic?

2

You want g_subprocess_wait() or g_subprocess_wait_check(), or the async variants. :slight_smile:

3

I’ve seen them, for example look at this flow:

GSubprocess *proc = g_subprocess_new(G_SUBPROCESS_FLAGS_STDOUT_PIPE, &err, PING, ..., NULL);
...

// at some point there's a user request to stop it
// and there's a stopper on this event
void stop_proc(GSubprocess *proc) {
   if (!proc) return;    
   g_subprocess_send_signal(proc, SIGTERM);
   // sleep_msec(100);
   if (is_proc_still_running(proc)) g_subprocess_force_exit(proc); 
  ...
   GError *err = NULL;                           
   g_subprocess_wait(proc, NULL, &err);
   if (err) { WARN("subprocess wait", err); } else {                                          
     int rc = g_subprocess_get_status(proc);
     g_print("finished (rc=%d)\n", rc); // LOG
   }
}

i.e. does it need to register callback somewhere with
g_subprocess_wait_check_async (subprocess, cancellable, callback, user_data);
just to set a flag in ‘callback’ that indicates the subprocess finish?
Isn’t there any simpler way to get is_subprocess_still_running(GSubprocess *proc)?

4

Yes, that’s how you’re going to want to do it. I see all of the related functions cannot be used until after wait has returned.

5

that’s how you’re going to want to do it

to not add extra code just for one bool flag, I thought that maybe there’s some flag already exist in that subprocess structure (that indicates a subprocess state)

Thank you for hints

6

You can call g_subprocess_get_identifier() to see if it returns a non-NULL value. If you want to wait for the process to finish, you should use g_subprocess_wait_check_async() or the synchronous variant, though

1 Like
7

Thank you very much for suggestion, you’re right, g_subprocess_get_identifier() one call suits much better for my case

8

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