🚀 go-pugleaf

Despite the help of several netters, I cannot seem to master the 
mechanics of inter-process communication via pipes. Ultimately,
I want 2-way communication between a parent and child process.
This is what I've tried so far;

/*
* parent.c	launches child and should get child's output
* standard include files
*/

int pipes[2];


void cbfunc (Widget w, XtPointer data, XtPointer dummy);

main (int argc, char **argv)
{

	XtAppContext app_parent;
	Widget topLevel;

	topLevel = XtVaAppInitialize (&app_parent, "Parent", NULL, 0,
				&argc, argv, NULL, NULL);
	pipe (pipes);

	if (fork() != 0)
	{
		XtAppAddInput (app_parent, pipes[0], XtInputReadMask, 
				cbfunc, NULL);
	}
	else
	{
		status = dup2 (pipes[1], STDOUT_FILENO);
		close (pipes[0]);
		if (status < 0)
		{	
			fprintf (stderr, "pipe error\n");
			exit (0);
		}
		execlp ("child", "child", (char *)0);
	}

	XtRealizeWidget (topLevel);
	XtAppMainLoop (app_parent);
}
	  
void cbfunc (Widget w, XtPointer data, XtPointer dummy)
{
	char buf[BUFSIZE] = "\0";

	read (pipes[0], buf, sizeof(buf));
	fprintf (stderr, "in Parent buf=%s\n", buf);
}



/*
*
* child.c	prints to stdout & stderr every 10 seconds
* necessary includes
*/


void alarmcb (void);

main (void)
{
	XtAppContext app_child;

	app_child = XtCreateApplicationContext ();
	signal (SIGALM, alarmcb);
	alarm (10);

	XtAppMainLoop (app_child);
}

void alarmcb (void)
{
	fprintf (stdout, "in child \n");
	fprinf (stderr, "in child\n");
	signal (SIGALM, alarmcb);
	alarm (10);
}
	
	
Everything runs, the child prints to the screen via the stderr and I get
no error codes, but the parent callback func is never entered. Could
anyone please tell me what the error is?

--thanks in advance, steve
-- 
Steve Langer  			       sglanger@argo.acs.oakland.edu (VMS)
Oakland University		       sglanger@vela.acs.oakland.edu (Ultrix)
---------------------------------------------------------------------------
Standard disclaimers apply. In addition, the author makes no guarantees,
concerning the grammatical accuracy of his writing. Therefore, any ^B's, ^C's, 
midword character additions/deletions and other non-sense which occurs (after 
the work leaves the author's decade old text editor via his decade old Amiga, 
struggles through a local 1200 baud Merit server to be further mauled via the 
remote VAX mail servers) is someone elses problem - namely yours.
---------------------------------------------------------------------------