Function: process-running-child-p

process-running-child-p is a function defined in process.c.

Signature

(process-running-child-p &optional PROCESS)

Documentation

Return non-nil if PROCESS has given the terminal to a child. If the operating system does not make it possible to find out, return t. If we can find out, return the numeric ID of the foreground process group.

Probably introduced at or before Emacs version 20.4.

Source Code

// Defined in /usr/src/emacs/src/process.c
{
  /* Initialize in case ioctl doesn't exist or gives an error,
     in a way that will cause returning t.  */
  Lisp_Object proc = get_process (process);
  struct Lisp_Process *p = XPROCESS (proc);

  if (!EQ (p->type, Qreal))
    error ("Process %s is not a subprocess",
	   SDATA (p->name));
  if (p->infd < 0)
    error ("Process %s is not active",
	   SDATA (p->name));

  pid_t gid = emacs_get_tty_pgrp (p);

  if (gid == p->pid)
    return Qnil;
  if (gid != -1)
    return make_fixnum (gid);
  return Qt;
}