X-Recipient: archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status: No, hits=-1.3 required=5.0	tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_NEUTRAL
X-Spam-Check-By: sourceware.org
Message-ID: <4EA329A3.30800@cornell.edu>
Date: Sat, 22 Oct 2011 16:37:55 -0400
From: Ken Brown <kbrown AT cornell DOT edu>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1
MIME-Version: 1.0
To: cygwin <cygwin AT cygwin DOT com>
Subject: gdb problem
Content-Type: multipart/mixed; boundary="------------020501000804040503070108"
X-IsSubscribed: yes
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

--------------020501000804040503070108
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

The attached testcase illustrates a problem with `gdb -i=mi'.  I've 
tested both gdb 7.3.50-1 and 7.3.50-2, with cygwin 1.7.9 as well as with 
several recent snapshots (including 2011-10-22).

Under some circumstances, if gdb -i=mi is started and given several 
input lines at once, it only prints part of the output before stopping. 
  I've been able to reproduce this once in a while while working 
interactively (by copying and pasting the whole bunch of input lines); 
in this case one can press Return to get the rest of the output.  But 
the problem happens consistently with the attached test case, which runs 
gdb in a subprocess.  One has to kill the gdb process before the main 
program exits.

The STC runs as expected on Linux.

The particular input lines I gave gdb are precisely those that emacs 
sends in the problem I reported in

   http://cygwin.com/ml/cygwin/2011-10/msg00357.html .

I don't know if this is relevant.

Ken

--------------020501000804040503070108
Content-Type: text/plain;
 name="stc.c"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="stc.c"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pty.h>
#include <string.h>
#include <sys/wait.h>

void get_output (int fd);

int
main () 
{
  int master;
  pid_t pid;

  if ((pid = forkpty (&master, NULL, NULL, NULL)) < 0)
    {
      perror ("forkpty");
      exit (1);
    }
  /* child */
  if (pid == 0) 
    {
      char  *argv[3];
      argv[0] = "gdb";
      argv[1] = "-i=mi";
      argv[2] = '\0';
      execvp (argv[0], argv);
      /* shouldn't get here */
      exit (1);
    }
  /* parent */
  char *input[10];

  input[0] = "1-inferior-tty-set /dev/pty3\n";
  input[1] = "2-gdb-set height 0\n";
  input[2] = "3-gdb-set non-stop 1\n";
  input[3] = "4-file-list-exec-source-files\n";
  input[4] = "5-file-list-exec-source-file\n";
  input[5] = "6-gdb-show prompt\n";
  input[6] = "7-stack-info-frame\n";
  input[7] = "8-thread-info\n";
  input[8] = "9-break-list\n";
  input[9] = "q\n";

  int i;
  for (i = 0; i < 10; ++i)
    write (master, input[i], strlen (input[i]));
  get_output (master);
  wait (NULL);
}

void
get_output (int fd)
{
#define BUFSIZE 1024
  char buf[BUFSIZE];
  int i;

  for (i = 0; i < 10; ++i)
    {
      int nread;
      nread = read (fd, buf, BUFSIZE);
      if (nread > 0)
	write (STDOUT_FILENO, buf, nread);
      else
	{
	  printf ("No more output.\n");
	  break;
	}
    }
}


--------------020501000804040503070108
Content-Type: text/plain; charset=us-ascii

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
--------------020501000804040503070108--