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/* Asynchronous subprocess control for GNU Emacs.
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   Copyright (C) 1985, 1986, 1987, 1988, 1992, 1993 Free Software Foundation, Inc.
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This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


#include <signal.h>

#include "config.h"

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/* This file is split into two parts by the following preprocessor
   conditional.  The 'then' clause contains all of the support for
   asynchronous subprocesses.  The 'else' clause contains stub
   versions of some of the asynchronous subprocess routines that are
   often called elsewhere in Emacs, so we don't have to #ifdef the
   sections that call them.  */


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#ifdef subprocesses

#include <stdio.h>
#include <errno.h>
#include <setjmp.h>
#include <sys/types.h>		/* some typedefs are used in sys/file.h */
#include <sys/file.h>
#include <sys/stat.h>

#ifdef HAVE_SOCKETS	/* TCP connection support, if kernel can do it */
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif /* HAVE_SOCKETS */

#if defined(BSD) || defined(STRIDE)
#include <sys/ioctl.h>
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#if !defined (O_NDELAY) && defined (HAVE_PTYS) && !defined(USG5)
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#include <fcntl.h>
#endif /* HAVE_PTYS and no O_NDELAY */
#endif /* BSD or STRIDE */

#ifdef NEED_BSDTTY
#include <bsdtty.h>
#endif

#ifdef IRIS
#include <sys/sysmacros.h>	/* for "minor" */
#endif /* not IRIS */

#include "systime.h"
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#include "systty.h"
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#include "lisp.h"
#include "window.h"
#include "buffer.h"
#include "process.h"
#include "termhooks.h"
#include "termopts.h"
#include "commands.h"
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#include "frame.h"
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Lisp_Object Qrun, Qstop, Qsignal, Qopen, Qclosed;
/* Qexit is declared and initialized in eval.c.  */

/* a process object is a network connection when its childp field is neither
   Qt nor Qnil but is instead a string (name of foreign host we
   are connected to + name of port we are connected to) */

#ifdef HAVE_SOCKETS
static Lisp_Object stream_process;

#define NETCONN_P(p) (XGCTYPE (XPROCESS (p)->childp) == Lisp_String)
#else
#define NETCONN_P(p) 0
#endif /* HAVE_SOCKETS */

/* Define first descriptor number available for subprocesses.  */
#ifdef VMS
#define FIRST_PROC_DESC 1
#else /* Not VMS */
#define FIRST_PROC_DESC 3
#endif

/* Define SIGCHLD as an alias for SIGCLD.  There are many conditionals
   testing SIGCHLD.  */

#if !defined (SIGCHLD) && defined (SIGCLD)
#define SIGCHLD SIGCLD
#endif /* SIGCLD */

#include "syssignal.h"

/* Define the structure that the wait system call stores.
   On many systems, there is a structure defined for this.
   But on vanilla-ish USG systems there is not.  */

#ifndef VMS
#ifndef WAITTYPE
#if !defined (BSD) && !defined (UNIPLUS) && !defined (STRIDE) && !(defined (HPUX) && !defined (NOMULTIPLEJOBS)) && !defined (HAVE_WAIT_HEADER)
#define WAITTYPE int
#define WIFSTOPPED(w) ((w&0377) == 0177)
#define WIFSIGNALED(w) ((w&0377) != 0177 && (w&~0377) == 0)
#define WIFEXITED(w) ((w&0377) == 0)
#define WRETCODE(w) (w >> 8)
#define WSTOPSIG(w) (w >> 8)
#define WTERMSIG(w) (w & 0377)
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#ifndef WCOREDUMP
#define WCOREDUMP(w) ((w&0200) != 0)
#endif
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#else 
#ifdef BSD4_1
#include <wait.h>
#else
#include <sys/wait.h>
#endif /* not BSD 4.1 */

#define WAITTYPE union wait
#define WRETCODE(w) w.w_retcode
#define WCOREDUMP(w) w.w_coredump

#ifdef HPUX
/* HPUX version 7 has broken definitions of these.  */
#undef WTERMSIG
#undef WSTOPSIG
#undef WIFSTOPPED
#undef WIFSIGNALED
#undef WIFEXITED
#endif

#ifndef WTERMSIG
#define WTERMSIG(w) w.w_termsig
#endif
#ifndef WSTOPSIG
#define WSTOPSIG(w) w.w_stopsig
#endif
#ifndef WIFSTOPPED
#define WIFSTOPPED(w) (WTERMSIG (w) == 0177)
#endif
#ifndef WIFSIGNALED
#define WIFSIGNALED(w) (WTERMSIG (w) != 0177 && (WSTOPSIG (w)) == 0)
#endif
#ifndef WIFEXITED
#define WIFEXITED(w) (WTERMSIG (w) == 0)
#endif
#endif /* BSD or UNIPLUS or STRIDE */
#endif /* no WAITTYPE */
#else /* VMS */
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#define WAITTYPE int
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#define WIFSTOPPED(w) 0
#define WIFSIGNALED(w) 0
#define WIFEXITED(w) ((w) != -1)
#define WRETCODE(w) (w)
#define WSTOPSIG(w) (w)
#define WCOREDUMP(w) 0
#define WTERMSIG(w) (w)
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#include <ssdef.h>
#include <iodef.h>
#include <clidef.h>
#include "vmsproc.h"
#endif /* VMS */

extern errno;
extern sys_nerr;
extern char *sys_errlist[];

#ifndef VMS
#ifndef BSD4_1
extern char *sys_siglist[];
#else
char *sys_siglist[] =
  {
    "bum signal!!",
    "hangup",
    "interrupt",
    "quit",
    "illegal instruction",
    "trace trap",
    "iot instruction",
    "emt instruction",
    "floating point exception",
    "kill",
    "bus error",
    "segmentation violation",
    "bad argument to system call",
    "write on a pipe with no one to read it",
    "alarm clock",
    "software termination signal from kill",
    "status signal",
    "sendable stop signal not from tty",
    "stop signal from tty",
    "continue a stopped process",
    "child status has changed",
    "background read attempted from control tty",
    "background write attempted from control tty",
    "input record available at control tty",
    "exceeded CPU time limit",
    "exceeded file size limit"
    };
#endif
#endif /* VMS */

/* t means use pty, nil means use a pipe,
   maybe other values to come.  */
Lisp_Object Vprocess_connection_type;

#ifdef SKTPAIR
#ifndef HAVE_SOCKETS
#include <sys/socket.h>
#endif
#endif /* SKTPAIR */

/* Number of events of change of status of a process.  */
int process_tick;

/* Number of events for which the user or sentinel has been notified.  */
int update_tick;

#ifdef FD_SET
/* We could get this from param.h, but better not to depend on finding that.
   And better not to risk that it might define other symbols used in this
   file.  */
#define MAXDESC 64
#define SELECT_TYPE fd_set
#else /* no FD_SET */
#define MAXDESC 32
#define SELECT_TYPE int

/* Define the macros to access a single-int bitmap of descriptors.  */
#define FD_SET(n, p) (*(p) |= (1 << (n)))
#define FD_CLR(n, p) (*(p) &= ~(1 << (n)))
#define FD_ISSET(n, p) (*(p) & (1 << (n)))
#define FD_ZERO(p) (*(p) = 0)
#endif /* no FD_SET */

/* Mask of bits indicating the descriptors that we wait for input on */

SELECT_TYPE input_wait_mask;

int delete_exited_processes;

/* Indexed by descriptor, gives the process (if any) for that descriptor */
Lisp_Object chan_process[MAXDESC];

/* Alist of elements (NAME . PROCESS) */
Lisp_Object Vprocess_alist;

Lisp_Object Qprocessp;

Lisp_Object get_process ();

/* Buffered-ahead input char from process, indexed by channel.
   -1 means empty (no char is buffered).
   Used on sys V where the only way to tell if there is any
   output from the process is to read at least one char.
   Always -1 on systems that support FIONREAD.  */

int proc_buffered_char[MAXDESC];

/* Compute the Lisp form of the process status, p->status, from
   the numeric status that was returned by `wait'.  */

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Lisp_Object status_convert ();

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update_status (p)
     struct Lisp_Process *p;
{
  union { int i; WAITTYPE wt; } u;
  u.i = XFASTINT (p->raw_status_low) + (XFASTINT (p->raw_status_high) << 16);
  p->status = status_convert (u.wt);
  p->raw_status_low = Qnil;
  p->raw_status_high = Qnil;
}

/*  Convert a process status work in Unix format to 
    the list that we use internally.  */

Lisp_Object
status_convert (w)
     WAITTYPE w;
{
  if (WIFSTOPPED (w))
    return Fcons (Qstop, Fcons (make_number (WSTOPSIG (w)), Qnil));
  else if (WIFEXITED (w))
    return Fcons (Qexit, Fcons (make_number (WRETCODE (w)),
				WCOREDUMP (w) ? Qt : Qnil));
  else if (WIFSIGNALED (w))
    return Fcons (Qsignal, Fcons (make_number (WTERMSIG (w)),
				  WCOREDUMP (w) ? Qt : Qnil));
  else
    return Qrun;
}

/* Given a status-list, extract the three pieces of information
   and store them individually through the three pointers.  */

void
decode_status (l, symbol, code, coredump)
     Lisp_Object l;
     Lisp_Object *symbol;
     int *code;
     int *coredump;
{
  Lisp_Object tem;

  if (XTYPE (l) == Lisp_Symbol)
    {
      *symbol = l;
      *code = 0;
      *coredump = 0;
    }
  else
    {
      *symbol = XCONS (l)->car;
      tem = XCONS (l)->cdr;
      *code = XFASTINT (XCONS (tem)->car);
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      tem = XCONS (tem)->cdr;
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      *coredump = !NILP (tem);
    }
}

/* Return a string describing a process status list.  */

Lisp_Object 
status_message (status)
     Lisp_Object status;
{
  Lisp_Object symbol;
  int code, coredump;
  Lisp_Object string, string2;

  decode_status (status, &symbol, &code, &coredump);

  if (EQ (symbol, Qsignal) || EQ (symbol, Qstop))
    {
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#ifndef VMS
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      string = build_string (code < NSIG ? sys_siglist[code] : "unknown");
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#else
      string = build_string (code < NSIG ? sys_errlist[code] : "unknown");
#endif
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      string2 = build_string (coredump ? " (core dumped)\n" : "\n");
      XSTRING (string)->data[0] = DOWNCASE (XSTRING (string)->data[0]);
      return concat2 (string, string2);
    }
  else if (EQ (symbol, Qexit))
    {
      if (code == 0)
	return build_string ("finished\n");
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      string = Fnumber_to_string (make_number (code));
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      string2 = build_string (coredump ? " (core dumped)\n" : "\n");
      return concat2 (build_string ("exited abnormally with code "),
		      concat2 (string, string2));
    }
  else
    return Fcopy_sequence (Fsymbol_name (symbol));
}

#ifdef HAVE_PTYS

/* Open an available pty, returning a file descriptor.
   Return -1 on failure.
   The file name of the terminal corresponding to the pty
   is left in the variable pty_name.  */

char pty_name[24];

int
allocate_pty ()
{
  struct stat stb;
  register c, i;
  int fd;

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  /* Some systems name their pseudoterminals so that there are gaps in
     the usual sequence - for example, on HP9000/S700 systems, there
     are no pseudoterminals with names ending in 'f'.  So we wait for
     three failures in a row before deciding that we've reached the
     end of the ptys.  */
  int failed_count = 0;

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#ifdef PTY_ITERATION
  PTY_ITERATION
#else
  for (c = FIRST_PTY_LETTER; c <= 'z'; c++)
    for (i = 0; i < 16; i++)
#endif
      {
#ifdef PTY_NAME_SPRINTF
	PTY_NAME_SPRINTF
#else
	sprintf (pty_name, "/dev/pty%c%x", c, i);
#endif /* no PTY_NAME_SPRINTF */

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#ifdef PTY_OPEN
	PTY_OPEN;
#else /* no PTY_OPEN */
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#ifdef IRIS
	/* Unusual IRIS code */
 	*ptyv = open ("/dev/ptc", O_RDWR | O_NDELAY, 0);
 	if (fd < 0)
 	  return -1;
	if (fstat (fd, &stb) < 0)
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	  return -1;
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#else /* not IRIS */
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	if (stat (pty_name, &stb) < 0)
	  {
	    failed_count++;
	    if (failed_count >= 3)
	      return -1;
	  }
	else
	  failed_count = 0;
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#ifdef O_NONBLOCK
	fd = open (pty_name, O_RDWR | O_NONBLOCK, 0);
#else
	fd = open (pty_name, O_RDWR | O_NDELAY, 0);
#endif
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#endif /* not IRIS */
#endif /* no PTY_OPEN */
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	if (fd >= 0)
	  {
	    /* check to make certain that both sides are available
	       this avoids a nasty yet stupid bug in rlogins */
#ifdef PTY_TTY_NAME_SPRINTF
	    PTY_TTY_NAME_SPRINTF
#else
            sprintf (pty_name, "/dev/tty%c%x", c, i);
#endif /* no PTY_TTY_NAME_SPRINTF */
#ifndef UNIPLUS
	    if (access (pty_name, 6) != 0)
	      {
		close (fd);
#ifndef IRIS
		continue;
#else
		return -1;
#endif /* IRIS */
	      }
#endif /* not UNIPLUS */
	    setup_pty (fd);
	    return fd;
	  }
      }
  return -1;
}
#endif /* HAVE_PTYS */

Lisp_Object
make_process (name)
     Lisp_Object name;
{
  register Lisp_Object val, tem, name1;
  register struct Lisp_Process *p;
  char suffix[10];
  register int i;

  /* size of process structure includes the vector header,
     so deduct for that.  But struct Lisp_Vector includes the first
     element, thus deducts too much, so add it back.  */
  val = Fmake_vector (make_number ((sizeof (struct Lisp_Process)
				    - sizeof (struct Lisp_Vector)
				    + sizeof (Lisp_Object))
				   / sizeof (Lisp_Object)),
		      Qnil);
  XSETTYPE (val, Lisp_Process);

  p = XPROCESS (val);
  XFASTINT (p->infd) = 0;
  XFASTINT (p->outfd) = 0;
  XFASTINT (p->pid) = 0;
  XFASTINT (p->tick) = 0;
  XFASTINT (p->update_tick) = 0;
  p->raw_status_low = Qnil;
  p->raw_status_high = Qnil;
  p->status = Qrun;
  p->mark = Fmake_marker ();

  /* If name is already in use, modify it until it is unused.  */

  name1 = name;
  for (i = 1; ; i++)
    {
      tem = Fget_process (name1);
      if (NILP (tem)) break;
      sprintf (suffix, "<%d>", i);
      name1 = concat2 (name, build_string (suffix));
    }
  name = name1;
  p->name = name;
  Vprocess_alist = Fcons (Fcons (name, val), Vprocess_alist);
  return val;
}

remove_process (proc)
     register Lisp_Object proc;
{
  register Lisp_Object pair;

  pair = Frassq (proc, Vprocess_alist);
  Vprocess_alist = Fdelq (pair, Vprocess_alist);
  Fset_marker (XPROCESS (proc)->mark, Qnil, Qnil);

  deactivate_process (proc);
}

DEFUN ("processp", Fprocessp, Sprocessp, 1, 1, 0,
  "Return t if OBJECT is a process.")
  (obj)
     Lisp_Object obj;
{
  return XTYPE (obj) == Lisp_Process ? Qt : Qnil;
}

DEFUN ("get-process", Fget_process, Sget_process, 1, 1, 0,
  "Return the process named NAME, or nil if there is none.")
  (name)
     register Lisp_Object name;
{
  if (XTYPE (name) == Lisp_Process)
    return name;
  CHECK_STRING (name, 0);
  return Fcdr (Fassoc (name, Vprocess_alist));
}

DEFUN ("get-buffer-process", Fget_buffer_process, Sget_buffer_process, 1, 1, 0,
  "Return the (or, a) process associated with BUFFER.\n\
BUFFER may be a buffer or the name of one.")
  (name)
     register Lisp_Object name;
{
  register Lisp_Object buf, tail, proc;

  if (NILP (name)) return Qnil;
  buf = Fget_buffer (name);
  if (NILP (buf)) return Qnil;

  for (tail = Vprocess_alist; !NILP (tail); tail = Fcdr (tail))
    {
      proc = Fcdr (Fcar (tail));
      if (XTYPE (proc) == Lisp_Process && EQ (XPROCESS (proc)->buffer, buf))
	return proc;
    }
  return Qnil;
}

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/* This is how commands for the user decode process arguments.  It
   accepts a process, a process name, a buffer, a buffer name, or nil.
   Buffers denote the first process in the buffer, and nil denotes the
   current buffer.  */
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Lisp_Object
get_process (name)
     register Lisp_Object name;
{
  register Lisp_Object proc;
  if (NILP (name))
    proc = Fget_buffer_process (Fcurrent_buffer ());
  else
    {
      proc = Fget_process (name);
      if (NILP (proc))
	proc = Fget_buffer_process (Fget_buffer (name));
    }

  if (!NILP (proc))
    return proc;

  if (NILP (name))
    error ("Current buffer has no process");
  else
    error ("Process %s does not exist", XSTRING (name)->data);
  /* NOTREACHED */
}

DEFUN ("delete-process", Fdelete_process, Sdelete_process, 1, 1, 0,
  "Delete PROCESS: kill it and forget about it immediately.\n\
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PROCESS may be a process, a buffer, the name of a process or buffer, or\n\
nil, indicating the current buffer's process.")
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  (proc)
     register Lisp_Object proc;
{
  proc = get_process (proc);
  XPROCESS (proc)->raw_status_low = Qnil;
  XPROCESS (proc)->raw_status_high = Qnil;
  if (NETCONN_P (proc))
    {
      XPROCESS (proc)->status = Fcons (Qexit, Fcons (make_number (0), Qnil));
      XSETINT (XPROCESS (proc)->tick, ++process_tick);
    }
  else if (XFASTINT (XPROCESS (proc)->infd))
    {
      Fkill_process (proc, Qnil);
      /* Do this now, since remove_process will make sigchld_handler do nothing.  */
      XPROCESS (proc)->status 
	= Fcons (Qsignal, Fcons (make_number (SIGKILL), Qnil));
      XSETINT (XPROCESS (proc)->tick, ++process_tick);
      status_notify ();
    }
  remove_process (proc);
  return Qnil;
}

DEFUN ("process-status", Fprocess_status, Sprocess_status, 1, 1, 0,
  "Return the status of PROCESS: a symbol, one of these:\n\
run  -- for a process that is running.\n\
stop -- for a process stopped but continuable.\n\
exit -- for a process that has exited.\n\
signal -- for a process that has got a fatal signal.\n\
open -- for a network stream connection that is open.\n\
closed -- for a network stream connection that is closed.\n\
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nil -- if arg is a process name and no such process exists.\n\
PROCESS may be a process, a buffer, the name of a process or buffer, or\n\
nil, indicating the current buffer's process.")
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/* command -- for a command channel opened to Emacs by another process.\n\
   external -- for an i/o channel opened to Emacs by another process.\n\  */
  (proc)
     register Lisp_Object proc;
{
  register struct Lisp_Process *p;
  register Lisp_Object status;
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  proc = get_process (proc);
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  if (NILP (proc))
    return proc;
  p = XPROCESS (proc);
  if (!NILP (p->raw_status_low))
    update_status (p);
  status = p->status;
  if (XTYPE (status) == Lisp_Cons)
    status = XCONS (status)->car;
  if (NETCONN_P (proc))
    {
      if (EQ (status, Qrun))
	status = Qopen;
      else if (EQ (status, Qexit))
	status = Qclosed;
    }
  return status;
}

DEFUN ("process-exit-status", Fprocess_exit_status, Sprocess_exit_status,
       1, 1, 0,
  "Return the exit status of PROCESS or the signal number that killed it.\n\
If PROCESS has not yet exited or died, return 0.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  if (!NILP (XPROCESS (proc)->raw_status_low))
    update_status (XPROCESS (proc));
  if (XTYPE (XPROCESS (proc)->status) == Lisp_Cons)
    return XCONS (XCONS (XPROCESS (proc)->status)->cdr)->car;
  return make_number (0);
}

DEFUN ("process-id", Fprocess_id, Sprocess_id, 1, 1, 0,
  "Return the process id of PROCESS.\n\
This is the pid of the Unix process which PROCESS uses or talks to.\n\
For a network connection, this value is nil.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->pid;
}

DEFUN ("process-name", Fprocess_name, Sprocess_name, 1, 1, 0,
  "Return the name of PROCESS, as a string.\n\
This is the name of the program invoked in PROCESS,\n\
possibly modified to make it unique among process names.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->name;
}

DEFUN ("process-command", Fprocess_command, Sprocess_command, 1, 1, 0,
  "Return the command that was executed to start PROCESS.\n\
This is a list of strings, the first string being the program executed\n\
and the rest of the strings being the arguments given to it.\n\
For a non-child channel, this is nil.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->command;
}

DEFUN ("set-process-buffer", Fset_process_buffer, Sset_process_buffer,
  2, 2, 0,
  "Set buffer associated with PROCESS to BUFFER (a buffer, or nil).")
  (proc, buffer)
     register Lisp_Object proc, buffer;
{
  CHECK_PROCESS (proc, 0);
  if (!NILP (buffer))
    CHECK_BUFFER (buffer, 1);
  XPROCESS (proc)->buffer = buffer;
  return buffer;
}

DEFUN ("process-buffer", Fprocess_buffer, Sprocess_buffer,
  1, 1, 0,
  "Return the buffer PROCESS is associated with.\n\
Output from PROCESS is inserted in this buffer\n\
unless PROCESS has a filter.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->buffer;
}

DEFUN ("process-mark", Fprocess_mark, Sprocess_mark,
  1, 1, 0,
  "Return the marker for the end of the last output from PROCESS.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->mark;
}

DEFUN ("set-process-filter", Fset_process_filter, Sset_process_filter,
  2, 2, 0,
  "Give PROCESS the filter function FILTER; nil means no filter.\n\
When a process has a filter, each time it does output\n\
the entire string of output is passed to the filter.\n\
The filter gets two arguments: the process and the string of output.\n\
If the process has a filter, its buffer is not used for output.")
  (proc, filter)
     register Lisp_Object proc, filter;
{
  CHECK_PROCESS (proc, 0);
  XPROCESS (proc)->filter = filter;
  return filter;
}

DEFUN ("process-filter", Fprocess_filter, Sprocess_filter,
  1, 1, 0,
  "Returns the filter function of PROCESS; nil if none.\n\
See `set-process-filter' for more info on filter functions.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->filter;
}

DEFUN ("set-process-sentinel", Fset_process_sentinel, Sset_process_sentinel,
  2, 2, 0,
  "Give PROCESS the sentinel SENTINEL; nil for none.\n\
The sentinel is called as a function when the process changes state.\n\
It gets two arguments: the process, and a string describing the change.")
  (proc, sentinel)
     register Lisp_Object proc, sentinel;
{
  CHECK_PROCESS (proc, 0);
  XPROCESS (proc)->sentinel = sentinel;
  return sentinel;
}

DEFUN ("process-sentinel", Fprocess_sentinel, Sprocess_sentinel,
  1, 1, 0,
  "Return the sentinel of PROCESS; nil if none.\n\
See `set-process-sentinel' for more info on sentinels.")
  (proc)
     register Lisp_Object proc;
{
  CHECK_PROCESS (proc, 0);
  return XPROCESS (proc)->sentinel;
}

DEFUN ("process-kill-without-query", Fprocess_kill_without_query,
  Sprocess_kill_without_query, 1, 2, 0,
  "Say no query needed if PROCESS is running when Emacs is exited.\n\
Optional second argument if non-nill says to require a query.\n\
Value is t if a query was formerly required.")
  (proc, value)
     register Lisp_Object proc, value;
{
  Lisp_Object tem;

  CHECK_PROCESS (proc, 0);
  tem = XPROCESS (proc)->kill_without_query;
  XPROCESS (proc)->kill_without_query = Fnull (value);

  return Fnull (tem);
}

Lisp_Object
list_processes_1 ()
{
  register Lisp_Object tail, tem;
  Lisp_Object proc, minspace, tem1;
  register struct buffer *old = current_buffer;
  register struct Lisp_Process *p;
  register int state;
  char tembuf[80];

  XFASTINT (minspace) = 1;

  set_buffer_internal (XBUFFER (Vstandard_output));
  Fbuffer_disable_undo (Vstandard_output);

  current_buffer->truncate_lines = Qt;

  write_string ("\
Proc         Status   Buffer         Command\n\
----         ------   ------         -------\n", -1);

  for (tail = Vprocess_alist; !NILP (tail); tail = Fcdr (tail))
    {
      Lisp_Object symbol;

      proc = Fcdr (Fcar (tail));
      p = XPROCESS (proc);
      if (NILP (p->childp))
	continue;

      Finsert (1, &p->name);
      Findent_to (make_number (13), minspace);

      if (!NILP (p->raw_status_low))
	update_status (p);
      symbol = p->status;
      if (XTYPE (p->status) == Lisp_Cons)
	symbol = XCONS (p->status)->car;

      
      if (EQ (symbol, Qsignal))
	{
	  Lisp_Object tem;
	  tem = Fcar (Fcdr (p->status));
#ifdef VMS
	  if (XINT (tem) < NSIG)
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	    write_string (sys_errlist [XINT (tem)], -1);
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	  else
#endif
	    Fprinc (symbol, Qnil);
	}
      else if (NETCONN_P (proc))
	{
	  if (EQ (symbol, Qrun))
	    write_string ("open", -1);
	  else if (EQ (symbol, Qexit))
	    write_string ("closed", -1);
	  else
	    Fprinc (symbol, Qnil);
	}
      else
	Fprinc (symbol, Qnil);

      if (EQ (symbol, Qexit))
	{
	  Lisp_Object tem;
	  tem = Fcar (Fcdr (p->status));
	  if (XFASTINT (tem))
	    {
	      sprintf (tembuf, " %d", XFASTINT (tem));
	      write_string (tembuf, -1);
	    }
	}

      if (EQ (symbol, Qsignal) || EQ (symbol, Qexit))
	remove_process (proc);

      Findent_to (make_number (22), minspace);
      if (NILP (p->buffer))
	insert_string ("(none)");
      else if (NILP (XBUFFER (p->buffer)->name))
	insert_string ("(Killed)");
      else
	Finsert (1, &XBUFFER (p->buffer)->name);

      Findent_to (make_number (37), minspace);

      if (NETCONN_P (proc))
        {
	  sprintf (tembuf, "(network stream connection to %s)\n",
		   XSTRING (p->childp)->data);
	  insert_string (tembuf);
        }
      else 
	{
	  tem = p->command;
	  while (1)
	    {
	      tem1 = Fcar (tem);
	      Finsert (1, &tem1);
	      tem = Fcdr (tem);
	      if (NILP (tem))
		break;
	      insert_string (" ");
	    }
	  insert_string ("\n");
       }
    }
  return Qnil;
}

DEFUN ("list-processes", Flist_processes, Slist_processes, 0, 0, "",
  "Display a list of all processes.\n\
\(Any processes listed as Exited or Signaled are actually eliminated\n\
after the listing is made.)")
  ()
{
  internal_with_output_to_temp_buffer ("*Process List*",
				       list_processes_1, Qnil);
  return Qnil;
}

DEFUN ("process-list", Fprocess_list, Sprocess_list, 0, 0, 0,
  "Return a list of all processes.")
  ()
{
  return Fmapcar (Qcdr, Vprocess_alist);
}

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/* Starting asynchronous inferior processes.  */

static Lisp_Object start_process_unwind ();

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DEFUN ("start-process", Fstart_process, Sstart_process, 3, MANY, 0,
  "Start a program in a subprocess.  Return the process object for it.\n\
Args are NAME BUFFER PROGRAM &rest PROGRAM-ARGS\n\
NAME is name for process.  It is modified if necessary to make it unique.\n\
BUFFER is the buffer or (buffer-name) to associate with the process.\n\
 Process output goes at end of that buffer, unless you specify\n\
 an output stream or filter function to handle the output.\n\
 BUFFER may be also nil, meaning that this process is not associated\n\
 with any buffer\n\
Third arg is program file name.  It is searched for as in the shell.\n\
Remaining arguments are strings to give program as arguments.")
  (nargs, args)
     int nargs;
     register Lisp_Object *args;
{
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  Lisp_Object buffer, name, program, proc, current_dir, tem;
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#ifdef VMS
  register unsigned char *new_argv;
  int len;
#else
  register unsigned char **new_argv;
#endif
  register int i;
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  int count = specpdl_ptr - specpdl;
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  buffer = args[1];
  if (!NILP (buffer))
    buffer = Fget_buffer_create (buffer);

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  /* Make sure that the child will be able to chdir to the current
     buffer's current directory, or its unhandled equivalent.  We
     can't just have the child check for an error when it does the
     chdir, since it's in a vfork.

     We have to GCPRO around this because Fexpand_file_name and
     Funhandled_file_name_directory might call a file name handling
     function.  The argument list is protected by the caller, so all
     we really have to worry about is buffer.  */
  {
    struct gcpro gcpro1, gcpro2;

    current_dir = current_buffer->directory;

    GCPRO2 (buffer, current_dir);

    current_dir = 
      expand_and_dir_to_file
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	(Funhandled_file_name_directory (current_dir), Qnil);
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    if (NILP (Ffile_accessible_directory_p (current_dir)))
      report_file_error ("Setting current directory",
			 Fcons (current_buffer->directory, Qnil));

    UNGCPRO;
  }

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  name = args[0];
  CHECK_STRING (name, 0);

  program = args[2];

  CHECK_STRING (program, 2);

#ifdef VMS
  /* Make a one member argv with all args concatenated
     together separated by a blank.  */
  len = XSTRING (program)->size + 2;
  for (i = 3; i < nargs; i++)
    {
      tem = args[i];
      CHECK_STRING (tem, i);
      len += XSTRING (tem)->size + 1;	/* count the blank */
    }
  new_argv = (unsigned char *) alloca (len);
  strcpy (new_argv, XSTRING (program)->data);
  for (i = 3; i < nargs; i++)
    {
      tem = args[i];
      CHECK_STRING (tem, i);
      strcat (new_argv, " ");
      strcat (new_argv, XSTRING (tem)->data);
    }
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  /* Need to add code here to check for program existence on VMS */
  
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#else /* not VMS */
  new_argv = (unsigned char **) alloca ((nargs - 1) * sizeof (char *));

  for (i = 3; i < nargs; i++)
    {
      tem = args[i];
      CHECK_STRING (tem, i);
      new_argv[i - 2] = XSTRING (tem)->data;
    }
  new_argv[i - 2] = 0;
  new_argv[0] = XSTRING (program)->data;

  /* If program file name is not absolute, search our path for it */
  if (new_argv[0][0] != '/')
    {
      tem = Qnil;
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      openp (Vexec_path, program, EXEC_SUFFIXES, &tem, 1);
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      if (NILP (tem))
	report_file_error ("Searching for program", Fcons (program, Qnil));
      new_argv[0] = XSTRING (tem)->data;
    }
#endif /* not VMS */

  proc = make_process (name);
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  /* If an error occurs and we can't start the process, we want to
     remove it from the process list.  This means that each error
     check in create_process doesn't need to call remove_process
     itself; it's all taken care of here.  */
  record_unwind_protect (start_process_unwind, proc);
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  XPROCESS (proc)->childp = Qt;
  XPROCESS (proc)->command_channel_p = Qnil;
  XPROCESS (proc)->buffer = buffer;
  XPROCESS (proc)->sentinel = Qnil;
  XPROCESS (proc)->filter = Qnil;
  XPROCESS (proc)->command = Flist (nargs - 2, args + 2);

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  create_process (proc, new_argv, current_dir);
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  return unbind_to (count, proc);
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}

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/* This function is the unwind_protect form for Fstart_process.  If
   PROC doesn't have its pid set, then we know someone has signalled
   an error and the process wasn't started successfully, so we should
   remove it from the process list.  */
static Lisp_Object
start_process_unwind (proc)
     Lisp_Object proc;
{
  if (XTYPE (proc) != Lisp_Process)
    abort ();

  /* Was PROC started successfully?  */
  if (XPROCESS (proc)->pid <= 0)
    remove_process (proc);

  return Qnil;
}


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SIGTYPE
create_process_1 (signo)
     int signo;
{
#ifdef USG
  /* USG systems forget handlers when they are used;
     must reestablish each time */
  signal (signo, create_process_1);
#endif /* USG */
}

#if 0  /* This doesn't work; see the note before sigchld_handler.  */
#ifdef USG
#ifdef SIGCHLD
/* Mimic blocking of signals on system V, which doesn't really have it.  */

/* Nonzero means we got a SIGCHLD when it was supposed to be blocked.  */
int sigchld_deferred;

SIGTYPE
create_process_sigchld ()
{
  signal (SIGCHLD, create_process_sigchld);

  sigchld_deferred = 1;
}
#endif
#endif
#endif

#ifndef VMS /* VMS version of this function is in vmsproc.c.  */
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create_process (process, new_argv, current_dir)
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     Lisp_Object process;
     char **new_argv;
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     Lisp_Object current_dir;
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{
  int pid, inchannel, outchannel, forkin, forkout;
  int sv[2];
#ifdef SIGCHLD
  SIGTYPE (*sigchld)();
#endif
  int pty_flag = 0;
  extern char **environ;

  inchannel = outchannel = -1;

#ifdef HAVE_PTYS
  if (EQ (Vprocess_connection_type, Qt))
    outchannel = inchannel = allocate_pty ();

  if (inchannel >= 0)
    {
#ifndef USG 
      /* On USG systems it does not work to open the pty's tty here
	       and then close and reopen it in the child.  */
#ifdef O_NOCTTY
      /* Don't let this terminal become our controlling terminal
	 (in case we don't have one).  */
      forkout = forkin = open (pty_name, O_RDWR | O_NOCTTY, 0);
#else
      forkout = forkin = open (pty_name, O_RDWR, 0);
#endif
      if (forkin < 0)
	report_file_error ("Opening pty", Qnil);
#else
      forkin = forkout = -1;
#endif /* not USG */
      pty_flag = 1;
    }
  else
#endif /* HAVE_PTYS */
#ifdef SKTPAIR
    {
      if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv) < 0)
	report_file_error ("Opening socketpair", Qnil);
      outchannel = inchannel = sv[0];
      forkout = forkin = sv[1];
    }
#else /* not SKTPAIR */
    {
      pipe (sv);
      inchannel = sv[0];
      forkout = sv[1];
      pipe (sv);
      outchannel = sv[1];
      forkin = sv[0];
    }
#endif /* not SKTPAIR */

#if 0
  /* Replaced by close_process_descs */
  set_exclusive_use (inchannel);
  set_exclusive_use (outchannel);
#endif

/* Stride people say it's a mystery why this is needed
   as well as the O_NDELAY, but that it fails without this.  */
#if defined (STRIDE) || (defined (pfa) && defined (HAVE_PTYS))
  {
    int one = 1;
    ioctl (inchannel, FIONBIO, &one);
  }
#endif

#ifdef O_NONBLOCK
  fcntl (inchannel, F_SETFL, O_NONBLOCK);
#else
#ifdef O_NDELAY
  fcntl (inchannel, F_SETFL, O_NDELAY);
#endif
#endif

  /* Record this as an active process, with its channels.
     As a result, child_setup will close Emacs's side of the pipes.  */
  chan_process[inchannel] = process;
  XFASTINT (XPROCESS (process)->infd) = inchannel;
  XFASTINT (XPROCESS (process)->outfd) = outchannel;
  /* Record the tty descriptor used in the subprocess.  */
  if (forkin < 0)
    XPROCESS (process)->subtty = Qnil;
  else
    XFASTINT (XPROCESS (process)->subtty) = forkin;
  XPROCESS (process)->pty_flag = (pty_flag ? Qt : Qnil);
  XPROCESS (process)->status = Qrun;

  /* Delay interrupts until we have a chance to store
     the new fork's pid in its process structure */
#ifdef SIGCHLD
#ifdef BSD4_1
  sighold (SIGCHLD);
#else /* not BSD4_1 */
#if defined (BSD) || defined (UNIPLUS) || defined (HPUX)
  sigsetmask (sigmask (SIGCHLD));
#else /* ordinary USG */
#if 0
  sigchld_deferred = 0;
  sigchld = signal (SIGCHLD, create_process_sigchld);
#endif
#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */

  /* Until we store the proper pid, enable sigchld_handler
     to recognize an unknown pid as standing for this process.
     It is very important not to let this `marker' value stay
     in the table after this function has returned; if it does
     it might cause call-process to hang and subsequent asynchronous
     processes to get their return values scrambled.  */
  XSETINT (XPROCESS (process)->pid, -1);

  {
    /* child_setup must clobber environ on systems with true vfork.
       Protect it from permanent change.  */
    char **save_environ = environ;

    pid = vfork ();
    if (pid == 0)
      {
	int xforkin = forkin;
	int xforkout = forkout;

#if 0 /* This was probably a mistake--it duplicates code later on,
	 but fails to handle all the cases.  */
	/* Make sure SIGCHLD is not blocked in the child.  */
	sigsetmask (SIGEMPTYMASK);
#endif

	/* Make the pty be the controlling terminal of the process.  */
#ifdef HAVE_PTYS
	/* First, disconnect its current controlling terminal.  */
#ifdef HAVE_SETSID
	setsid ();
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#ifdef TIOCSCTTY
	/* Make the pty's terminal the controlling terminal.  */
	if (pty_flag && (ioctl (xforkin, TIOCSCTTY, 0) < 0))
	  abort ();
#endif
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#else /* not HAVE_SETSID */
#ifdef USG
	/* It's very important to call setpgrp() here and no time
	   afterwards.  Otherwise, we lose our controlling tty which
	   is set when we open the pty. */
	setpgrp ();
#endif /* USG */
#endif /* not HAVE_SETSID */
#ifdef TIOCNOTTY 
	/* In 4.3BSD, the TIOCSPGRP bug has been fixed, and now you
	   can do TIOCSPGRP only to the process's controlling tty.  */
	if (pty_flag)
	  {
	    /* I wonder: would just ioctl (0, TIOCNOTTY, 0) work here? 
	       I can't test it since I don't have 4.3.  */
	    int j = open ("/dev/tty", O_RDWR, 0);
	    ioctl (j, TIOCNOTTY, 0);
	    close (j);
#ifndef USG
	    /* In order to get a controlling terminal on some versions
	       of BSD, it is necessary to put the process in pgrp 0
	       before it opens the terminal.  */
	    setpgrp (0, 0);
#endif
	  }
#endif /* TIOCNOTTY */

#if !defined (RTU) && !defined (UNIPLUS)
/*** There is a suggestion that this ought to be a
     conditional on TIOCSPGRP.  */
	/* Now close the pty (if we had it open) and reopen it.
	   This makes the pty the controlling terminal of the subprocess.  */
	if (pty_flag)
	  {
	    /* I wonder if close (open (pty_name, ...)) would work?  */
	    if (xforkin >= 0)
	      close (xforkin);
	    xforkout = xforkin = open (pty_name, O_RDWR, 0);

	    if (xforkin < 0)
	      abort ();
	  }
#endif /* not UNIPLUS and not RTU */
#ifdef SETUP_SLAVE_PTY
	SETUP_SLAVE_PTY;
#endif /* SETUP_SLAVE_PTY */
#ifdef AIX
	/* On AIX, we've disabled SIGHUP above once we start a child on a pty.
	   Now reenable it in the child, so it will die when we want it to.  */
	if (pty_flag)
	  signal (SIGHUP, SIG_DFL);
#endif
#endif /* HAVE_PTYS */

#ifdef SIGCHLD
#ifdef BSD4_1
	sigrelse (SIGCHLD);
#else /* not BSD4_1 */
#if defined (BSD) || defined (UNIPLUS) || defined (HPUX)
	sigsetmask (SIGEMPTYMASK);
#else /* ordinary USG */
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#if 0
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	signal (SIGCHLD, sigchld);
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#endif
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#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */

	child_setup_tty (xforkout);
	child_setup (xforkin, xforkout, xforkout,
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		     new_argv, 1, current_dir);
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      }
    environ = save_environ;
  }

  if (pid < 0)
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    report_file_error ("Doing vfork", Qnil);
  
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  XFASTINT (XPROCESS (process)->pid) = pid;

  FD_SET (inchannel, &input_wait_mask);

  /* If the subfork execv fails, and it exits,
     this close hangs.  I don't know why.
     So have an interrupt jar it loose.  */
  stop_polling ();
  signal (SIGALRM, create_process_1);
  alarm (1);
#ifdef SYSV4_PTYS
  /* OK to close only if it's not a pty.  Otherwise we need to leave
     it open for ioctl to get pgrp when signals are sent, or to send
     the interrupt characters through if that's how we're signalling
     subprocesses.  Alternately if you are concerned about running out
     of file descriptors, you could just save the tty name and open
     just to do the ioctl.  */
  if (NILP (XFASTINT (XPROCESS (process)->pty_flag)))
#endif
    {
      XPROCESS (process)->subtty = Qnil;
      if (forkin >= 0)
	close (forkin);
    }
  alarm (0);
  start_polling ();
  if (forkin != forkout && forkout >= 0)
    close (forkout);

#ifdef SIGCHLD
#ifdef BSD4_1
  sigrelse (SIGCHLD);
#else /* not BSD4_1 */
#if defined (BSD) || defined (UNIPLUS) || defined (HPUX)
  sigsetmask (SIGEMPTYMASK);
#else /* ordinary USG */
#if 0
  signal (SIGCHLD, sigchld);
  /* Now really handle any of these signals
     that came in during this function.  */
  if (sigchld_deferred)
    kill (getpid (), SIGCHLD);
#endif
#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */
}
#endif /* not VMS */

#ifdef HAVE_SOCKETS

/* open a TCP network connection to a given HOST/SERVICE.  Treated
   exactly like a normal process when reading and writing.  Only
   differences are in status display and process deletion.  A network
   connection has no PID; you cannot signal it.  All you can do is
   deactivate and close it via delete-process */

DEFUN ("open-network-stream", Fopen_network_stream, Sopen_network_stream, 
       4, 4, 0, 
  "Open a TCP connection for a service to a host.\n\
Returns a subprocess-object to represent the connection.\n\
Input and output work as for subprocesses; `delete-process' closes it.\n\
Args are NAME BUFFER HOST SERVICE.\n\
NAME is name for process.  It is modified if necessary to make it unique.\n\
BUFFER is the buffer (or buffer-name) to associate with the process.\n\
 Process output goes at end of that buffer, unless you specify\n\
 an output stream or filter function to handle the output.\n\
 BUFFER may be also nil, meaning that this process is not associated\n\
 with any buffer\n\
Third arg is name of the host to connect to, or its IP address.\n\
Fourth arg SERVICE is name of the service desired, or an integer\n\
 specifying a port number to connect to.")
   (name, buffer, host, service)
      Lisp_Object name, buffer, host, service;
{
  Lisp_Object proc;
  register int i;
  struct sockaddr_in address;
  struct servent *svc_info;
  struct hostent *host_info_ptr, host_info;
  char *(addr_list[2]);
  unsigned long numeric_addr;
  int s, outch, inch;
  char errstring[80];
  int port;
  struct hostent host_info_fixed;
  struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;

  GCPRO4 (name, buffer, host, service);
  CHECK_STRING (name, 0);
  CHECK_STRING (host, 0);
  if (XTYPE(service) == Lisp_Int)
    port = htons ((unsigned short) XINT (service));
  else
    {
      CHECK_STRING (service, 0);
      svc_info = getservbyname (XSTRING (service)->data, "tcp");
      if (svc_info == 0)
	error ("Unknown service \"%s\"", XSTRING (service)->data);
      port = svc_info->s_port;
    }

  host_info_ptr = gethostbyname (XSTRING (host)->data);
  if (host_info_ptr == 0)
    /* Attempt to interpret host as numeric inet address */
    {
      numeric_addr = inet_addr (XSTRING (host)->data);
      if (numeric_addr == -1)
	error ("Unknown host \"%s\"", XSTRING (host)->data);

      host_info_ptr = &host_info;
      host_info.h_name = 0;
      host_info.h_aliases = 0;
      host_info.h_addrtype = AF_INET;
      host_info.h_addr_list  =  &(addr_list[0]);
      addr_list[0] = (char*)(&numeric_addr);
      addr_list[1] = 0;
      host_info.h_length = strlen (addr_list[0]);
    }

  bzero (&address, sizeof address);
  bcopy (host_info_ptr->h_addr, (char *) &address.sin_addr,
	 host_info_ptr->h_length);
  address.sin_family = host_info_ptr->h_addrtype;
  address.sin_port = port;

  s = socket (host_info_ptr->h_addrtype, SOCK_STREAM, 0);
  if (s < 0) 
    report_file_error ("error creating socket", Fcons (name, Qnil));

 loop:
  if (connect (s, &address, sizeof address) == -1)
    {
      int xerrno = errno;
      if (errno == EINTR)
	goto loop;
      close (s);
      errno = xerrno;
      report_file_error ("connection failed",
			 Fcons (host, Fcons (name, Qnil)));
    }

  inch = s;
  outch = dup (s);
  if (outch < 0) 
    report_file_error ("error duplicating socket", Fcons (name, Qnil));

  if (!NILP (buffer))
    buffer = Fget_buffer_create (buffer);
  proc = make_process (name);

  chan_process[inch] = proc;

#ifdef O_NONBLOCK
  fcntl (inch, F_SETFL, O_NONBLOCK);
#else
#ifdef O_NDELAY
  fcntl (inch, F_SETFL, O_NDELAY);
#endif
#endif

  XPROCESS (proc)->childp = host;
  XPROCESS (proc)->command_channel_p = Qnil;
  XPROCESS (proc)->buffer = buffer;
  XPROCESS (proc)->sentinel = Qnil;
  XPROCESS (proc)->filter = Qnil;
  XPROCESS (proc)->command = Qnil;
  XPROCESS (proc)->pid = Qnil;
  XFASTINT (XPROCESS (proc)->infd) = s;
  XFASTINT (XPROCESS (proc)->outfd) = outch;
  XPROCESS (proc)->status = Qrun;
  FD_SET (inch, &input_wait_mask);

  UNGCPRO;
  return proc;
}
#endif	/* HAVE_SOCKETS */

deactivate_process (proc)
     Lisp_Object proc;
{
  register int inchannel, outchannel;
  register struct Lisp_Process *p = XPROCESS (proc);

  inchannel = XFASTINT (p->infd);
  outchannel = XFASTINT (p->outfd);

  if (inchannel)
    {
      /* Beware SIGCHLD hereabouts. */
      flush_pending_output (inchannel);
#ifdef VMS
      {
	VMS_PROC_STUFF *get_vms_process_pointer (), *vs;
	sys$dassgn (outchannel);
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	vs = get_vms_process_pointer (p->pid);
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	if (vs)
	  give_back_vms_process_stuff (vs);
      }
#else
      close (inchannel);
      if (outchannel && outchannel != inchannel)
 	close (outchannel);
#endif

      XFASTINT (p->infd) = 0;
      XFASTINT (p->outfd) = 0;
      chan_process[inchannel] = Qnil;
      FD_CLR (inchannel, &input_wait_mask);
    }
}

/* Close all descriptors currently in use for communication
   with subprocess.  This is used in a newly-forked subprocess
   to get rid of irrelevant descriptors.  */

close_process_descs ()
{
  int i;
  for (i = 0; i < MAXDESC; i++)
    {
      Lisp_Object process;
      process = chan_process[i];
      if (!NILP (process))
	{
	  int in = XFASTINT (XPROCESS (process)->infd);
	  int out = XFASTINT (XPROCESS (process)->outfd);
	  if (in)
	    close (in);
	  if (out && in != out)
	    close (out);
	}
    }
}

DEFUN ("accept-process-output", Faccept_process_output, Saccept_process_output,
  0, 3, 0,
  "Allow any pending output from subprocesses to be read by Emacs.\n\
It is read into the process' buffers or given to their filter functions.\n\
Non-nil arg PROCESS means do not return until some output has been received\n\
from PROCESS.\n\
Non-nil second arg TIMEOUT and third arg TIMEOUT-MSECS are number of\n\
seconds and microseconds to wait; return after that much time whether\n\
or not there is input.\n\
Return non-nil iff we received any output before the timeout expired.")
  (proc, timeout, timeout_msecs)
     register Lisp_Object proc, timeout, timeout_msecs;
{
  int seconds;
  int useconds;

  if (! NILP (timeout_msecs))
    {
      CHECK_NUMBER (timeout_msecs, 2);
      useconds = XINT (timeout_msecs);
      if (XTYPE (timeout) != Lisp_Int)
	XSET (timeout, Lisp_Int, 0);

      {
	int carry = useconds / 1000000;

	XSETINT (timeout, XINT (timeout) + carry);
	useconds -= carry * 1000000;

	/* I think this clause is necessary because C doesn't
	   guarantee a particular rounding direction for negative
	   integers.  */
	if (useconds < 0)
	  {
	    XSETINT (timeout, XINT (timeout) - 1);
	    useconds += 1000000;
	  }
      }
    }
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  else
    useconds = 0;
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  if (! NILP (timeout))
    {
      CHECK_NUMBER (timeout, 1);
      seconds = XINT (timeout);
      if (seconds <= 0)
	seconds = -1;
    }
  else
    {
      if (NILP (proc))
	seconds = -1;
      else
	seconds = 0;
    }

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  if (NILP (proc))
    XFASTINT (proc) = 0;

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  return
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    (wait_reading_process_input (seconds, useconds, proc, 0)
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     ? Qt : Qnil);
}

/* This variable is different from waiting_for_input in keyboard.c.
   It is used to communicate to a lisp process-filter/sentinel (via the
   function Fwaiting_for_user_input_p below) whether emacs was waiting
   for user-input when that process-filter was called.
   waiting_for_input cannot be used as that is by definition 0 when
   lisp code is being evalled */
static int waiting_for_user_input_p;

/* Read and dispose of subprocess output while waiting for timeout to
   elapse and/or keyboard input to be available.

   time_limit is:
     timeout in seconds, or
     zero for no limit, or
     -1 means gobble data immediately available but don't wait for any.

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   microsecs is:
     an additional duration to wait (if time_limit is greater than
     zero), specified in millisec.

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   read_kbd is a lisp value:
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     0 to ignore keyboard input, or
     1 to return when input is available, or
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     -1 meaning caller will actually read the input, so don't throw to
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       the quit handler, or
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     a cons cell, meaning wait wait until its car is non-nil, or
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     a process object, meaning wait until something arrives from that
       process.  The return value is true iff we read some input from
       that process.
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   do_display != 0 means redisplay should be done to show subprocess
   output that arrives.

   If read_kbd is a pointer to a struct Lisp_Process, then the
     function returns true iff we received input from that process
     before the timeout elapsed.
   Otherwise, return true iff we recieved input from any process.  */

wait_reading_process_input (time_limit, microsecs, read_kbd, do_display)
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     int time_limit, microsecs;
     Lisp_Object read_kbd;
     int do_display;
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{
  register int channel, nfds, m;
  static SELECT_TYPE Available;
  int xerrno;
  Lisp_Object proc;
  EMACS_TIME timeout, end_time, garbage;
  SELECT_TYPE Atemp;
  int wait_channel = 0;
  struct Lisp_Process *wait_proc = 0;
  int got_some_input = 0;
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  Lisp_Object *wait_for_cell = 0;
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  FD_ZERO (&Available);

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  /* If read_kbd is a process to watch, set wait_proc and wait_channel
     accordingly.  */
  if (XTYPE (read_kbd) == Lisp_Process)
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    {
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      wait_proc = XPROCESS (read_kbd);
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      wait_channel = XFASTINT (wait_proc->infd);
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      XFASTINT (read_kbd) = 0;
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    }

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  /* If waiting for non-nil in a cell, record where.  */
  if (XTYPE (read_kbd) == Lisp_Cons)
    {
      wait_for_cell = &XCONS (read_kbd)->car;
      XFASTINT (read_kbd) = 0;
    }

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  waiting_for_user_input_p = XINT (read_kbd);
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  /* Since we may need to wait several times,
     compute the absolute time to return at.  */
  if (time_limit || microsecs)
    {
      EMACS_GET_TIME (end_time);
      EMACS_SET_SECS_USECS (timeout, time_limit, microsecs);
      EMACS_ADD_TIME (end_time, end_time, timeout);
    }

  while (1)
    {
      /* If calling from keyboard input, do not quit
	 since we want to return C-g as an input character.
	 Otherwise, do pending quit if requested.  */
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      if (XINT (read_kbd) >= 0)
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	QUIT;

      /* Compute time from now till when time limit is up */
      /* Exit if already run out */
      if (time_limit == -1)
	{
	  /* -1 specified for timeout means
	     gobble output available now
	     but don't wait at all. */

	  EMACS_SET_SECS_USECS (timeout, 0, 0);
	}
      else if (time_limit || microsecs)
	{
	  EMACS_GET_TIME (timeout);
	  EMACS_SUB_TIME (timeout, end_time, timeout);
	  if (EMACS_TIME_NEG_P (timeout))
	    break;
	}
      else
	{
	  EMACS_SET_SECS_USECS (timeout, 100000, 0);
	}

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      /* If status of something has changed, and no input is
	 available, notify the user of the change right away.  After
	 this explicit check, we'll let the SIGCHLD handler zap
	 timeout to get our attention.  */
      if (update_tick != process_tick && do_display)
	{
	  Atemp = input_wait_mask;
	  EMACS_SET_SECS_USECS (timeout, 0, 0);
	  if (select (MAXDESC, &Atemp, 0, 0, &timeout) <= 0)
	    status_notify ();
	}

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      /* Cause C-g and alarm signals to take immediate action,
	 and cause input available signals to zero out timeout.

	 It is important that we do this before checking for process
	 activity.  If we get a SIGCHLD after the explicit checks for
	 process activity, timeout is the only way we will know.  */
      if (XINT (read_kbd) < 0)
	set_waiting_for_input (&timeout);

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      /* Don't wait for output from a non-running process.  */
      if (wait_proc != 0 && !NILP (wait_proc->raw_status_low))
	update_status (wait_proc);
      if (wait_proc != 0
	  && ! EQ (wait_proc->status, Qrun))
	break;

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      /* Wait till there is something to do */

      Available = input_wait_mask;
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      if (! XINT (read_kbd))
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	FD_CLR (0, &Available);

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      /* If frame size has changed or the window is newly mapped,
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	 redisplay now, before we start to wait.  There is a race
	 condition here; if a SIGIO arrives between now and the select
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	 and indicates that a frame is trashed, the select may block
	 displaying a trashed screen.  */
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      if (frame_garbaged)
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	redisplay_preserve_echo_area ();

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      if (XINT (read_kbd) && detect_input_pending ())
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	nfds = 0;
      else
	nfds = select (MAXDESC, &Available, 0, 0, &timeout);
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      xerrno = errno;

      /* Make C-g and alarm signals set flags again */
      clear_waiting_for_input ();

      /*  If we woke up due to SIGWINCH, actually change size now.  */
      do_pending_window_change ();

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      if (time_limit && nfds == 0) /* timeout elapsed */
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	break;
      if (nfds < 0)
	{
	  if (xerrno == EINTR)
	    FD_ZERO (&Available);
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#ifdef ultrix
	  /* Ultrix select seems to return ENOMEM when it is
	     interrupted.  Treat it just like EINTR.  Bleah.  Note
	     that we want to test for the "ultrix" CPP symbol, not
	     "__ultrix__"; the latter is only defined under GCC, but
	     not by DEC's bundled CC.  -JimB  */
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	  else if (xerrno == ENOMEM)
	    FD_ZERO (&Available);
#endif
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#ifdef ALLIANT
	  /* This happens for no known reason on ALLIANT.
	     I am guessing that this is the right response. -- RMS.  */
	  else if (xerrno == EFAULT)
	    FD_ZERO (&Available);
#endif
	  else if (xerrno == EBADF)
	    {
#ifdef AIX
	      /* AIX doesn't handle PTY closure the same way BSD does.  On AIX,
		 the child's closure of the pts gives the parent a SIGHUP, and
		 the ptc file descriptor is automatically closed,
		 yielding EBADF here or at select() call above.
		 So, SIGHUP is ignored (see def of PTY_TTY_NAME_SPRINTF
		 in m-ibmrt-aix.h), and here we just ignore the select error.
		 Cleanup occurs c/o status_notify after SIGCLD. */
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	      FD_ZERO (&Available); /* Cannot depend on values returned */
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#else
	      abort ();
#endif
	    }
	  else
	    error("select error: %s", sys_errlist[xerrno]);
	}
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#if defined(sun) && !defined(USG5_4)
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      else if (nfds > 0 && FD_ISSET (0, &Available) && interrupt_input)
	/* System sometimes fails to deliver SIGIO.  */
	kill (getpid (), SIGIO);
#endif

      /* Check for keyboard input */
      /* If there is any, return immediately
	 to give it higher priority than subprocesses */

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      if (XINT (read_kbd) && detect_input_pending ())
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	break;

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      /* Exit now if the cell we're waiting for became non-nil.  */
      if (wait_for_cell && ! NILP (*wait_for_cell))
	break;

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#ifdef SIGIO
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      /* If we think we have keyboard input waiting, but didn't get SIGIO
	 go read it.  This can happen with X on BSD after logging out.
	 In that case, there really is no input and no SIGIO,
	 but select says there is input.  */

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      if (XINT (read_kbd) && interrupt_input && (FD_ISSET (fileno (stdin), &Available)))
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	kill (0, SIGIO);
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#endif
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      if (! wait_proc)
	got_some_input |= nfds > 0;

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      /* If checking input just got us a size-change event from X,
	 obey it now if we should.  */
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      if (XINT (read_kbd))
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	do_pending_window_change ();

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      /* Check for data from a process or a command channel */
      for (channel = FIRST_PROC_DESC; channel < MAXDESC; channel++)
	{
	  if (FD_ISSET (channel, &Available))
	    {
	      int nread;

	      /* If waiting for this channel, arrange to return as
		 soon as no more input to be processed.  No more
		 waiting.  */
	      if (wait_channel == channel)
		{
		  wait_channel = 0;
		  time_limit = -1;
		  got_some_input = 1;
		}
	      proc = chan_process[channel];
	      if (NILP (proc))
		continue;

	      /* Read data from the process, starting with our
		 buffered-ahead character if we have one.  */

	      nread = read_process_output (proc, channel);
	      if (nread > 0)
		{
		  /* Since read_process_output can run a filter,
		     which can call accept-process-output,
		     don't try to read from any other processes
		     before doing the select again.  */
		  FD_ZERO (&Available);

		  if (do_display)
		    redisplay_preserve_echo_area ();
		}
#ifdef EWOULDBLOCK
	      else if (nread == -1 && errno == EWOULDBLOCK)
		;
#else
#ifdef O_NONBLOCK
	      else if (nread == -1 && errno == EAGAIN)
		;
#else
#ifdef O_NDELAY
	      else if (nread == -1 && errno == EAGAIN)
		;
	      /* Note that we cannot distinguish between no input
		 available now and a closed pipe.
		 With luck, a closed pipe will be accompanied by
		 subprocess termination and SIGCHLD.  */
	      else if (nread == 0 && !NETCONN_P (proc))
		;
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#endif				/* O_NDELAY */
#endif				/* O_NONBLOCK */
#endif				/* EWOULDBLOCK */
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#ifdef HAVE_PTYS
	      /* On some OSs with ptys, when the process on one end of
		 a pty exits, the other end gets an error reading with
		 errno = EIO instead of getting an EOF (0 bytes read).
		 Therefore, if we get an error reading and errno =
		 EIO, just continue, because the child process has
		 exited and should clean itself up soon (e.g. when we
		 get a SIGCHLD). */
	      else if (nread == -1 && errno == EIO)
		;
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#endif				/* HAVE_PTYS */
	      /* If we can detect process termination, don't consider the process
		 gone just because its pipe is closed.  */
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#ifdef SIGCHLD
	      else if (nread == 0 && !NETCONN_P (proc))
		;
#endif
	      else
		{
		  /* Preserve status of processes already terminated.  */
		  XSETINT (XPROCESS (proc)->tick, ++process_tick);
		  deactivate_process (proc);
		  if (!NILP (XPROCESS (proc)->raw_status_low))
		    update_status (XPROCESS (proc));
		  if (EQ (XPROCESS (proc)->status, Qrun))
		    XPROCESS (proc)->status
		      = Fcons (Qexit, Fcons (make_number (256), Qnil));
		}
	    }
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	}			/* end for each file descriptor */
    }				/* end while exit conditions not met */
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  /* If calling from keyboard input, do not quit
     since we want to return C-g as an input character.
     Otherwise, do pending quit if requested.  */
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  if (XINT (read_kbd) >= 0)
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    {
      /* Prevent input_pending from remaining set if we quit.  */
      clear_input_pending ();
      QUIT;
    }
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