src/syscalls.cc

/*

Copyright (C) 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005,
              2006, 2007, 2008, 2009 John W. Eaton

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

// Thomas Baier <baier@ci.tuwien.ac.at> added the original versions of
// the following functions:
//
//   mkfifo  unlink  waitpid

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <cstdio>
#include <cstring>

#include <sys/types.h>
#include <unistd.h>

#include <fcntl.h>

#include "file-ops.h"
#include "file-stat.h"
#include "oct-syscalls.h"
#include "oct-uname.h"

#include "defun.h"
#include "error.h"
#include "gripes.h"
#include "lo-utils.h"
#include "oct-map.h"
#include "oct-obj.h"
#include "oct-stdstrm.h"
#include "oct-stream.h"
#include "sysdep.h"
#include "utils.h"
#include "variables.h"
#include "input.h"

static Octave_map
mk_stat_map (const base_file_stat& fs)
{
  Octave_map m;

  m.assign ("dev", static_cast<double> (fs.dev ()));
  m.assign ("ino", fs.ino ());
  m.assign ("mode", fs.mode ());
  m.assign ("modestr", fs.mode_as_string ());
  m.assign ("nlink", fs.nlink ());
  m.assign ("uid", fs.uid ());
  m.assign ("gid", fs.gid ());
#if defined (HAVE_STRUCT_STAT_ST_RDEV)
  m.assign ("rdev", static_cast<double> (fs.rdev ()));
#endif
  m.assign ("size", fs.size ());
  m.assign ("atime", fs.atime ());
  m.assign ("mtime", fs.mtime ());
  m.assign ("ctime", fs.ctime ());
#if defined (HAVE_STRUCT_STAT_ST_BLKSIZE)
  m.assign ("blksize", fs.blksize ());
#endif
#if defined (HAVE_STRUCT_STAT_ST_BLOCKS)
  m.assign ("blocks", fs.blocks ());
#endif

  return m;
}

DEFUN (dup2, args, ,
 "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{fid}, @var{msg}] =} dup2 (@var{old}, @var{new})\n\
Duplicate a file descriptor.\n\
\n\
If successful, @var{fid} is greater than zero and contains the new file\n\
ID.  Otherwise, @var{fid} is negative and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 2)
    {
      octave_stream old_stream
	= octave_stream_list::lookup (args(0), "dup2");

      if (! error_state)
	{
	  octave_stream new_stream
	    = octave_stream_list::lookup (args(1), "dup2");

	  if (! error_state)
	    {
	      int i_old = old_stream.file_number ();
	      int i_new = new_stream.file_number ();

	      if (i_old >= 0 && i_new >= 0)
		{
		  std::string msg;

		  int status = octave_syscalls::dup2 (i_old, i_new, msg);

		  retval(0) = status;
		  retval(1) = msg;
		}
	    }
	}
      else
	error ("dup2: invalid stream");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (exec, args, ,
 "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{err}, @var{msg}] =} exec (@var{file}, @var{args})\n\
Replace current process with a new process.  Calling @code{exec} without\n\
first calling @code{fork} will terminate your current Octave process and\n\
replace it with the program named by @var{file}.  For example,\n\
\n\
@example\n\
exec (\"ls\" \"-l\")\n\
@end example\n\
\n\
@noindent\n\
will run @code{ls} and return you to your shell prompt.\n\
\n\
If successful, @code{exec} does not return.  If @code{exec} does return,\n\
@var{err} will be nonzero, and @var{msg} will contain a system-dependent\n\
error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 1 || nargin == 2)
    {
      std::string exec_file = args(0).string_value ();

      if (! error_state)
	{
	  string_vector exec_args;

	  if (nargin == 2)
	    {
	      string_vector tmp = args(1).all_strings ();

	      if (! error_state)
		{
		  int len = tmp.length ();

		  exec_args.resize (len + 1);

		  exec_args[0] = exec_file;

		  for (int i = 0; i < len; i++)
		    exec_args[i+1] = tmp[i];
		}
	      else
		error ("exec: arguments must be character strings");
	    }
	  else
	    {
	      exec_args.resize (1);

	      exec_args[0] = exec_file;
	    }

	  if (! error_state)
	    {
	      std::string msg;

	      int status = octave_syscalls::execvp (exec_file, exec_args, msg);

	      retval(0) = status;
	      retval(1) = msg;
	    }
	}
      else
	error ("exec: first argument must be a string");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (popen2, args, ,
 "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{in}, @var{out}, @var{pid}] =} popen2 (@var{command}, @var{args})\n\
Start a subprocess with two-way communication.  The name of the process\n\
is given by @var{command}, and @var{args} is an array of strings\n\
containing options for the command.  The file identifiers for the input\n\
and output streams of the subprocess are returned in @var{in} and\n\
@var{out}.  If execution of the command is successful, @var{pid}\n\
contains the process ID of the subprocess.  Otherwise, @var{pid} is\n\
@minus{}1.\n\
\n\
For example,\n\
\n\
@example\n\
[in, out, pid] = popen2 (\"sort\", \"-r\");\n\
fputs (in, \"these\\nare\\nsome\\nstrings\\n\");\n\
fclose (in);\n\
EAGAIN = errno (\"EAGAIN\");\n\
done = false;\n\
do\n\
  s = fgets (out);\n\
  if (ischar (s))\n\
    fputs (stdout, s);\n\
  elseif (errno () == EAGAIN)\n\
    sleep (0.1);\n\
    fclear (out);\n\
  else\n\
    done = true;\n\
  endif\n\
until (done)\n\
fclose (out);\n\
waitpid (pid);\n\
     @print{} these\n\
     @print{} strings\n\
     @print{} some\n\
     @print{} are\n\
@end example\n\
\n\
Note that @code{popen2}, unlike @code{popen}, will not \"reap\" the\n\
child process.  If you don't use @code{waitpid} to check the child's\n\
exit status, it will linger until Octave exits.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(2) = -1;
  retval(1) = Matrix ();
  retval(0) = Matrix ();

  int nargin = args.length ();

  if (nargin >= 1 && nargin <= 3)
    {
      std::string exec_file = args(0).string_value();

      if (! error_state)
        {
	  string_vector arg_list;

	  if (nargin >= 2)
	    {
	      string_vector tmp = args(1).all_strings ();

	      if (! error_state)
		{
		  int len = tmp.length ();

		  arg_list.resize (len + 1);

		  arg_list[0] = exec_file;

		  for (int i = 0; i < len; i++)
		    arg_list[i+1] = tmp[i];
		}
	      else
		error ("popen2: arguments must be character strings");
	    }
	  else
	    {
	      arg_list.resize (1);

	      arg_list[0] = exec_file;
	    }

          if (! error_state)
            {
              bool sync_mode = (nargin == 3 ? args(2).bool_value() : false);

              if (! error_state)
                {
                  int fildes[2];
                  std::string msg;
                  pid_t pid;

                  pid = octave_syscalls::popen2 (exec_file, arg_list, sync_mode, fildes, msg, interactive);
                  if (pid >= 0)
                    {
                      FILE *ifile = fdopen (fildes[1], "r");
                      FILE *ofile = fdopen (fildes[0], "w");

                      std::string nm;

                      octave_stream is = octave_stdiostream::create (nm, ifile,
                          std::ios::in);

                      octave_stream os = octave_stdiostream::create (nm, ofile,
                          std::ios::out);

                      Cell file_ids (1, 2);

                      retval(0) = octave_stream_list::insert (os);
                      retval(1) = octave_stream_list::insert (is);
					  retval(2) = pid;
                    }
				  else
                    error (msg.c_str ());
                }
            }
          else
            error ("popen2: arguments must be character strings");
        }
      else
        error ("popen2: first argument must be a string");
    }
  else
    print_usage ();

  return retval;
}

/*

%!test
%!  if (isunix())
%!    [in, out, pid] = popen2 ("sort", "-r");
%!    EAGAIN = errno ("EAGAIN");
%!  else
%!    [in, out, pid] = popen2 ("sort", "/R");
%!    EAGAIN = errno ("EINVAL");
%!  endif
%!  fputs (in, "these\nare\nsome\nstrings\n");
%!  fclose (in);
%!  done = false;
%!  str = {};
%!  idx = 0;
%!  errs = 0;
%!  do
%!     if (!isunix())
%!       errno (0);
%!     endif
%!     s = fgets (out);
%!     if (ischar (s))
%!       idx++;
%!       str{idx} = s;
%!     elseif (errno () == EAGAIN)
%!       fclear (out);
%!       sleep (0.1);
%!       if (++errs == 100)
%!         done = true;
%!       endif
%!     else
%!       done = true;
%!     endif
%!  until (done)
%!  fclose (out);
%!  if (isunix())
%!    assert(str,{"these\n","strings\n","some\n","are\n"})
%!  else
%!    assert(str,{"these\r\n","strings\r\n","some\r\n","are\r\n"})
%!  end

*/

DEFUNX ("fcntl", Ffcntl, args, ,
 "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{err}, @var{msg}] =} fcntl (@var{fid}, @var{request}, @var{arg})\n\
Change the properties of the open file @var{fid}.  The following values\n\
may be passed as @var{request}:\n\
\n\
@vtable @code\n\
@item F_DUPFD\n\
Return a duplicate file descriptor.\n\
\n\
@item F_GETFD\n\
Return the file descriptor flags for @var{fid}.\n\
\n\
@item F_SETFD\n\
Set the file descriptor flags for @var{fid}.\n\
\n\
@item F_GETFL\n\
Return the file status flags for @var{fid}.  The following codes may be\n\
returned (some of the flags may be undefined on some systems).\n\
\n\
@vtable @code\n\
@item O_RDONLY\n\
Open for reading only.\n\
\n\
@item O_WRONLY\n\
Open for writing only.\n\
\n\
@item O_RDWR\n\
Open for reading and writing.\n\
\n\
@item O_APPEND\n\
Append on each write.\n\
\n\
@item O_CREAT\n\
Create the file if it does not exist.\n\
\n\
@item O_NONBLOCK\n\
Nonblocking mode.\n\
\n\
@item O_SYNC\n\
Wait for writes to complete.\n\
\n\
@item O_ASYNC\n\
Asynchronous I/O.\n\
@end vtable\n\
\n\
@item F_SETFL\n\
Set the file status flags for @var{fid} to the value specified by\n\
@var{arg}.  The only flags that can be changed are @w{@code{O_APPEND}} and\n\
@w{@code{O_NONBLOCK}}.\n\
@end vtable\n\
\n\
If successful, @var{err} is 0 and @var{msg} is an empty string.\n\
Otherwise, @var{err} is nonzero and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 3)
    {
      octave_stream strm = octave_stream_list::lookup (args (0), "fcntl");

      if (! error_state)
	{
	  int fid = strm.file_number ();

	  int req = args(1).int_value (true);
	  int arg = args(2).int_value (true);

	  if (! error_state)
	    {
	      // FIXME -- Need better checking here?
	      if (fid < 0)
		error ("fcntl: invalid file id");
	      else
		{
		  std::string msg;

		  int status = octave_fcntl (fid, req, arg, msg);

		  retval(0) = status;
		  retval(1) = msg;
		}
	    }
	}
      else
	error ("fcntl: file id, request, and argument must be integers");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (fork, args, ,
 "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{pid}, @var{msg}] =} fork ()\n\
Create a copy of the current process.\n\
\n\
Fork can return one of the following values:\n\
\n\
@table @asis\n\
@item > 0\n\
You are in the parent process.  The value returned from @code{fork} is\n\
the process id of the child process.  You should probably arrange to\n\
wait for any child processes to exit.\n\
\n\
@item 0\n\
You are in the child process.  You can call @code{exec} to start another\n\
process.  If that fails, you should probably call @code{exit}.\n\
\n\
@item < 0\n\
The call to @code{fork} failed for some reason.  You must take evasive\n\
action.  A system dependent error message will be waiting in @var{msg}.\n\
@end table\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 0)
    {
      std::string msg;

      pid_t pid = octave_syscalls::fork (msg);

      retval(0) = pid;
      retval(1) = msg;
    }
  else
    print_usage ();

  return retval;
}

DEFUN (getpgrp, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {pgid =} getpgrp ()\n\
Return the process group id of the current process.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 0)
    {
      std::string msg;

      retval(0) = octave_syscalls::getpgrp (msg);
      retval(1) = msg;
    }
  else
    print_usage ();

  return retval;
}

DEFUN (getpid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {pid =} getpid ()\n\
Return the process id of the current process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::getpid ();
  else
    print_usage ();

  return retval;
}

DEFUN (getppid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {pid =} getppid ()\n\
Return the process id of the parent process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::getppid ();
  else
    print_usage ();

  return retval;
}

DEFUN (getegid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {egid =} getegid ()\n\
Return the effective group id of the current process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::getegid ();
  else
    print_usage ();

  return retval;
}

DEFUN (getgid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {gid =} getgid ()\n\
Return the real group id of the current process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::getgid ();
  else
    print_usage ();

  return retval;
}

DEFUN (geteuid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {euid =} geteuid ()\n\
Return the effective user id of the current process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::geteuid ();
  else
    print_usage ();

  return retval;
}

DEFUN (getuid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {uid =} getuid ()\n\
Return the real user id of the current process.\n\
@end deftypefn")
{
  octave_value retval = -1;

  int nargin = args.length ();

  if (nargin == 0)
    retval = octave_syscalls::getuid ();
  else
    print_usage ();

  return retval;
}

DEFUN (kill, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{err}, @var{msg}] =} kill (@var{pid}, @var{sig})\n\
Send signal @var{sig} to process @var{pid}.\n\
\n\
If @var{pid} is positive, then signal @var{sig} is sent to @var{pid}.\n\
\n\
If @var{pid} is 0, then signal @var{sig} is sent to every process\n\
in the process group of the current process.\n\
\n\
If @var{pid} is -1, then signal @var{sig} is sent to every process\n\
except process 1.\n\
\n\
If @var{pid} is less than -1, then signal @var{sig} is sent to every\n\
process in the process group @var{-pid}.\n\
\n\
If @var{sig} is 0, then no signal is sent, but error checking is still\n\
performed.\n\
\n\
Return 0 if successful, otherwise return -1.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  if (args.length () == 2)
    {
      pid_t pid = args(0).int_value (true);

      if (! error_state)
	{
	  int sig = args(1).int_value (true);

	  if (! error_state)
	    {
	      std::string msg;

	      int status = octave_syscalls::kill (pid, sig, msg);

	      retval(1) = msg;
	      retval(0) = status;
	    }
	}
    }
  else
    print_usage ();

  return retval;
}

DEFUN (fstat, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{info}, @var{err}, @var{msg}] =} fstat (@var{fid})\n\
Return information about the open file @var{fid}.  See @code{stat}\n\
for a description of the contents of @var{info}.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      int fid = octave_stream_list::get_file_number (args(0));

      if (! error_state)
	{
	  file_fstat fs (fid);

	  if (fs)
	    {
	      retval(2) = std::string ();
	      retval(1) = 0;
	      retval(0) = octave_value (mk_stat_map (fs));
	    }
	  else
	    {
	      retval(2) = fs.error ();
	      retval(1) = -1;
	      retval(0) = Matrix ();
	    }
	}
    }
  else
    print_usage ();

  return retval;
}

DEFUN (lstat, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{info}, @var{err}, @var{msg}] =} lstat (@var{file})\n\
See stat.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      std::string fname = args(0).string_value ();

      if (! error_state)
	{
	  file_stat fs (fname, false);

	  if (fs)
	    {
	      retval(2) = std::string ();
	      retval(1) = 0;
	      retval(0) = mk_stat_map (fs);
	    }
	  else
	    {
	      retval(2) = fs.error ();
	      retval(1) = -1;
	      retval(0) = Matrix ();
	    }
	}
    }
  else
    print_usage ();

  return retval;
}



DEFUNX ("mkfifo", Fmkfifo, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{err}, @var{msg}] =} mkfifo (@var{name}, @var{mode})\n\
Create a @var{fifo} special file named @var{name} with file mode @var{mode}\n\
\n\
If successful, @var{err} is 0 and @var{msg} is an empty string.\n\
Otherwise, @var{err} is nonzero and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 2)
    {
      if (args(0).is_string ())
	{
	  std::string name = args(0).string_value ();

	  if (args(1).is_scalar_type ())
	    {
	      long mode = args(1).long_value ();

	      if (! error_state)
		{
		  std::string msg;

		  int status = octave_mkfifo (name, mode, msg);

		  retval(0) = status;

		  if (status < 0)
		    retval(1) = msg;
		}
	      else
		error ("mkfifo: invalid MODE");
	    }
	  else
	    error ("mkfifo: MODE must be an integer");
	}
      else
	error ("mkfifo: file name must be a string");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (pipe, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{read_fd}, @var{write_fd}, @var{err}, @var{msg}] =} pipe ()\n\
Create a pipe and return the reading and writing ends of the pipe\n\
into @var{read_fd} and @var{write_fd} respectively.\n\
\n\
If successful, @var{err} is 0 and @var{msg} is an empty string.\n\
Otherwise, @var{err} is nonzero and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(3) = std::string ();
  retval(2) = -1;
  retval(1) = -1;
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 0)
    {
      int fid[2];

      std::string msg;

      int status = octave_syscalls::pipe (fid, msg);

      if (status < 0)
	retval(3) = msg;
      else
	{
	  FILE *ifile = fdopen (fid[0], "r");
	  FILE *ofile = fdopen (fid[1], "w");

	  std::string nm;

	  octave_stream is = octave_stdiostream::create (nm, ifile,
							 std::ios::in);

	  octave_stream os = octave_stdiostream::create (nm, ofile,
							 std::ios::out);

	  retval(1) = octave_stream_list::insert (os);
	  retval(0) = octave_stream_list::insert (is);

	  retval(2) = status;
	}
    }
  else
    print_usage ();

  return retval;
}

DEFUN (stat, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{info}, @var{err}, @var{msg}] =} stat (@var{file})\n\
@deftypefnx {Built-in Function} {[@var{info}, @var{err}, @var{msg}] =} lstat (@var{file})\n\
Return a structure @var{s} containing the following information about\n\
@var{file}.\n\
\n\
@table @code\n\
@item dev\n\
ID of device containing a directory entry for this file.\n\
\n\
@item ino\n\
File number of the file.\n\
\n\
@item mode\n\
File mode, as an integer.  Use the functions @w{@code{S_ISREG}},\n\
@w{@code{S_ISDIR}}, @w{@code{S_ISCHR}}, @w{@code{S_ISBLK}}, @w{@code{S_ISFIFO}},\n\
@w{@code{S_ISLNK}}, or @w{@code{S_ISSOCK}} to extract information from this\n\
value.\n\
\n\
@item modestr\n\
File mode, as a string of ten letters or dashes as would be returned by\n\
@kbd{ls -l}.\n\
\n\
@item nlink\n\
Number of links.\n\
\n\
@item uid\n\
User ID of file's owner.\n\
\n\
@item gid\n\
Group ID of file's group.\n\
\n\
@item rdev\n\
ID of device for block or character special files.\n\
\n\
@item size\n\
Size in bytes.\n\
\n\
@item atime\n\
Time of last access in the same form as time values returned from\n\
@code{time}.  @xref{Timing Utilities}.\n\
\n\
@item mtime\n\
Time of last modification in the same form as time values returned from\n\
@code{time}.  @xref{Timing Utilities}.\n\
\n\
@item ctime\n\
Time of last file status change in the same form as time values\n\
returned from @code{time}.  @xref{Timing Utilities}.\n\
\n\
@item blksize\n\
Size of blocks in the file.\n\
\n\
@item blocks\n\
Number of blocks allocated for file.\n\
@end table\n\
\n\
If the call is successful @var{err} is 0 and @var{msg} is an empty\n\
string.  If the file does not exist, or some other error occurs, @var{s}\n\
is an empty matrix, @var{err} is @minus{}1, and @var{msg} contains the\n\
corresponding system error message.\n\
\n\
If @var{file} is a symbolic link, @code{stat} will return information\n\
about the actual file that is referenced by the link.  Use @code{lstat}\n\
if you want information about the symbolic link itself.\n\
\n\
For example,\n\
\n\
@example\n\
[s, err, msg] = stat (\"/vmlinuz\")\n\
      @result{} s =\n\
        @{\n\
          atime = 855399756\n\
          rdev = 0\n\
          ctime = 847219094\n\
          uid = 0\n\
          size = 389218\n\
          blksize = 4096\n\
          mtime = 847219094\n\
          gid = 6\n\
          nlink = 1\n\
          blocks = 768\n\
          mode = -rw-r--r--\n\
          modestr = -rw-r--r--\n\
          ino = 9316\n\
          dev = 2049\n\
        @}\n\
     @result{} err = 0\n\
     @result{} msg = \n\
@end example\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      std::string fname = args(0).string_value ();

      if (! error_state)
	{
	  file_stat fs (fname);

	  if (fs)
	    {
	      retval(2) = std::string ();
	      retval(1) = 0;
	      retval(0) = octave_value (mk_stat_map (fs));
	    }
	  else
	    {
	      retval(2) = fs.error ();
	      retval(1) = -1;
	      retval(0) = Matrix ();
	    }
	}
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISREG", FS_ISREG, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISREG (@var{mode})\n\
Return true if @var{mode} corresponds to a regular file.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_reg (static_cast<mode_t> (mode));
      else
	error ("S_ISREG: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISDIR", FS_ISDIR, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISDIR (@var{mode})\n\
Return true if @var{mode} corresponds to a directory.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_dir (static_cast<mode_t> (mode));
      else
	error ("S_ISDIR: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISCHR", FS_ISCHR, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISCHR (@var{mode})\n\
Return true if @var{mode} corresponds to a character devicey.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_chr (static_cast<mode_t> (mode));
      else
	error ("S_ISCHR: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISBLK", FS_ISBLK, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISBLK (@var{mode})\n\
Return true if @var{mode} corresponds to a block device.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_blk (static_cast<mode_t> (mode));
      else
	error ("S_ISBLK: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISFIFO", FS_ISFIFO, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISFIFO (@var{mode})\n\
Return true if @var{mode} corresponds to a fifo.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_fifo (static_cast<mode_t> (mode));
      else
	error ("S_ISFIFO: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISLNK", FS_ISLNK, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISLNK (@var{mode})\n\
Return true if @var{mode} corresponds to a symbolic link.  The value\n\
of @var{mode} is assumed to be returned from a call to @code{stat}.\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_lnk (static_cast<mode_t> (mode));
      else
	error ("S_ISLNK: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("S_ISSOCK", FS_ISSOCK, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} S_ISSOCK (@var{mode})\n\
@seealso{stat, lstat}\n\
@end deftypefn")
{
  octave_value retval = false;

  if (args.length () == 1)
    {
      double mode = args(0).double_value ();

      if (! error_state)
	retval = file_stat::is_sock (static_cast<mode_t> (mode));
      else
	error ("S_ISSOCK: invalid mode value");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (uname, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{uts}, @var{err}, @var{msg}] =} uname ()\n\
Return system information in the structure.  For example,\n\
\n\
@example\n\
@group\n\
uname ()\n\
     @result{} @{\n\
           sysname = x86_64\n\
           nodename = segfault\n\
           release = 2.6.15-1-amd64-k8-smp\n\
           version = Linux\n\
           machine = #2 SMP Thu Feb 23 04:57:49 UTC 2006\n\
         @}\n\
@end group\n\
@end example\n\
\n\
If successful, @var{err} is 0 and @var{msg} is an empty string.\n\
Otherwise, @var{err} is nonzero and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 0)
    {
      octave_uname sysinfo;

      Octave_map m;

      m.assign ("sysname", sysinfo.sysname ());
      m.assign ("nodename", sysinfo.nodename ());
      m.assign ("release", sysinfo.release ());
      m.assign ("version", sysinfo.version ());
      m.assign ("machine", sysinfo.machine ());

      retval(2) = sysinfo.message ();
      retval(1) = sysinfo.error ();
      retval(0) = m;
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("unlink", Funlink, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{err}, @var{msg}] =} unlink (@var{file})\n\
Delete the file named @var{file}.\n\
\n\
If successful, @var{err} is 0 and @var{msg} is an empty string.\n\
Otherwise, @var{err} is nonzero and @var{msg} contains a\n\
system-dependent error message.\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(1) = std::string ();
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 1)
    {
      if (args(0).is_string ())
	{
	  std::string name = args(0).string_value ();

	  std::string msg;

	  int status = octave_unlink (name, msg);

	  retval(0) = status;
	  retval(1) = msg;	    
	}
      else
	error ("unlink: file name must be a string");
    }
  else
    print_usage ();

  return retval;
}

DEFUN (waitpid, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{pid}, @var{status}, @var{msg}] =} waitpid (@var{pid}, @var{options})\n\
Wait for process @var{pid} to terminate.  The @var{pid} argument can be:\n\
\n\
@table @asis\n\
@item @minus{}1\n\
Wait for any child process.\n\
\n\
@item 0\n\
Wait for any child process whose process group ID is equal to that of\n\
the Octave interpreter process.\n\
\n\
@item > 0\n\
Wait for termination of the child process with ID @var{pid}.\n\
@end table\n\
\n\
The @var{options} argument can be a bitwise OR of zero or more of\n\
the following constants:\n\
\n\
@table @code\n\
@item 0\n\
Wait until signal is received or a child process exits (this is the\n\
default if the @var{options} argument is missing).\n\
\n\
@item WNOHANG\n\
Do not hang if status is not immediately available.\n\
\n\
@item WUNTRACED\n\
Report the status of any child processes that are stopped, and whose\n\
status has not yet been reported since they stopped.\n\
\n\
@item WCONTINUE\n\
Return if a stopped child has been resumed by delivery of @code{SIGCONT}.\n\
This value may not be meaningful on all systems.\n\
@end table\n\
\n\
If the returned value of @var{pid} is greater than 0, it is the process\n\
ID of the child process that exited.  If an error occurs, @var{pid} will\n\
be less than zero and @var{msg} will contain a system-dependent error\n\
message.  The value of @var{status} contains additional system-dependent\n\
information about the subprocess that exited.\n\
@seealso{WCONTINUE, WCOREDUMP, WEXITSTATUS, WIFCONTINUED, WIFSIGNALED, WIFSTOPPED, WNOHANG, WSTOPSIG, WTERMSIG, WUNTRACED}\n\
@end deftypefn")
{
  octave_value_list retval;

  retval(2) = std::string ();
  retval(1) = 0;
  retval(0) = -1;

  int nargin = args.length ();

  if (nargin == 1 || nargin == 2)
    {
      pid_t pid = args(0).int_value (true);
  
      if (! error_state)
	{
	  int options = 0;

	  if (args.length () == 2)
	    options = args(1).int_value (true);

	  if (! error_state)
	    {
	      std::string msg;

	      int status = 0;

	      pid_t result = octave_syscalls::waitpid (pid, &status, options, msg);

	      retval(0) = result;
	      retval(1) = status;
	      retval(2) = msg;
	    }
	  else
	    error ("waitpid: OPTIONS must be an integer");
	}
      else
	error ("waitpid: PID must be an integer value");
    }
  else
    print_usage ();

  return retval;
}

DEFUNX ("WIFEXITED", FWIFEXITED, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WIFEXITED (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return true if the\n\
child terminated normally.\n\
@seealso{waitpid, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WCOREDUMP, WIFSTOPPED, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WIFEXITED)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WIFEXITED (status);
      else
	error ("WIFEXITED: expecting integer argument");
    }
#else
  warning ("WIFEXITED always returns false in this version of Octave")
#endif

  return retval;
}

DEFUNX ("WEXITSTATUS", FWEXITSTATUS, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WEXITSTATUS (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return the exit\n\
status of the child.  This function should only be employed if\n\
@code{WIFEXITED} returned true.\n\
@seealso{waitpid, WIFEXITED, WIFSIGNALED, WTERMSIG, WCOREDUMP, WIFSTOPPED, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WEXITSTATUS)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WEXITSTATUS (status);
      else
	error ("WEXITSTATUS: expecting integer argument");
    }
#else
  warning ("WEXITSTATUS always returns false in this version of Octave")
#endif

  return retval;
}

DEFUNX ("WIFSIGNALED", FWIFSIGNALED, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WIFSIGNALED (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return true if the\n\
child process was terminated by a signal.\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WTERMSIG, WCOREDUMP, WIFSTOPPED, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WIFSIGNALED)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WIFSIGNALED (status);
      else
	error ("WIFSIGNALED: expecting integer argument");
    }
#else
  warning ("WIFSIGNALED always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("WTERMSIG", FWTERMSIG, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WTERMSIG (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return the number of\n\
the signal that caused the child process to terminate.  This function\n\
should only be employed if @code{WIFSIGNALED} returned true.\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WIFSIGNALED, WCOREDUMP, WIFSTOPPED, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WTERMSIG)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WTERMSIG (status);
      else
	error ("WTERMSIG: expecting integer argument");
    }
#else
  warning ("WTERMSIG always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("WCOREDUMP", FWCOREDUMP, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WCOREDUMP (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return true if the\n\
child produced a core dump.  This function should only be employed if\n\
@code{WIFSIGNALED} returned true.  The macro used to implement this\n\
function is not specified in POSIX.1-2001 and is not available on some\n\
Unix implementations (e.g., AIX, SunOS).\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WIFSTOPPED, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WCOREDUMP)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WCOREDUMP (status);
      else
	error ("WCOREDUMP: expecting integer argument");
    }
#else
  warning ("WCOREDUMP always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("WIFSTOPPED", FWIFSTOPPED, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WIFSTOPPED (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return true if the\n\
child process was stopped by delivery of a signal; this is only\n\
possible if the call was done using @code{WUNTRACED} or when the child\n\
is being traced (see ptrace(2)).\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WCOREDUMP, WSTOPSIG, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WIFSTOPPED)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WIFSTOPPED (status);
      else
	error ("WIFSTOPPED: expecting integer argument");
    }
#else
  warning ("WIFSTOPPED always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("WSTOPSIG", FWSTOPSIG, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WSTOPSIG (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return the number of\n\
the signal which caused the child to stop.  This function should only\n\
be employed if @code{WIFSTOPPED} returned true.\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WCOREDUMP, WIFSTOPPED, WIFCONTINUED}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WSTOPSIG)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WSTOPSIG (status);
      else
	error ("WSTOPSIG: expecting integer argument");
    }
#else
  warning ("WSTOPSIG always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("WIFCONTINUED", FWIFCONTINUED, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WIFCONTINUED (@var{status})\n\
Given @var{status} from a call to @code{waitpid}, return true if the\n\
child process was resumed by delivery of @code{SIGCONT}.\n\
@seealso{waitpid, WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WCOREDUMP, WIFSTOPPED, WSTOPSIG}\n\
@end deftypefn")
{
  octave_value retval = 0.0;

#if defined (WIFCONTINUED)
  if (args.length () == 1)
    {
      int status = args(0).int_value ();

      if (! error_state)
	retval = WIFCONTINUED (status);
      else
	error ("WIFCONTINUED: expecting integer argument");
    }
#else
  warning ("WIFCONTINUED always returns false in this version of Octave");
#endif

  return retval;
}

DEFUNX ("canonicalize_file_name", Fcanonicalize_file_name, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {[@var{cname}, @var{status}, @var{msg}]} canonicalize_file_name (@var{name})\n\
Return the canonical name of file @var{name}.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      std::string name = args(0).string_value ();

      if (! error_state)
	{
	  std::string msg;

	  std::string result = octave_canonicalize_file_name (name, msg);

	  retval(2) = msg;
	  retval(1) = msg.empty () ? 0 : -1;
	  retval(0) = result;
	}
      else
	error ("canonicalize_file_name: argument must be a character string");
    }
  else
    print_usage ();

  return retval;
}

static octave_value
const_value (const octave_value_list& args, int val)
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin == 0)
    retval = val;
  else
    print_usage ();

  return retval;
}

#if !defined (O_NONBLOCK) && defined (O_NDELAY)
#define O_NONBLOCK O_NDELAY
#endif

#if defined (F_DUPFD)
DEFUNX ("F_DUPFD", FF_DUPFD, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} F_DUPFD ()\n\
Return the value required to request that @code{fcntl} return a\n\
duplicate file descriptor.\n\
@seealso{fcntl, F_GETFD, F_GETFL, F_SETFD, F_SETFL}\n\
@end deftypefn")
{
  return const_value (args, F_DUPFD);
}
#endif

#if defined (F_GETFD)
DEFUNX ("F_GETFD", FF_GETFD, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} F_GETFD ()\n\
Return the value required to request that @code{fcntl} to return the\n\
file descriptor flags.\n\
@seealso{fcntl, F_DUPFD, F_GETFL, F_SETFD, F_SETFL}\n\
@end deftypefn")
{
  return const_value (args, F_GETFD);
}
#endif

#if defined (F_GETFL)
DEFUNX ("F_GETFL", FF_GETFL, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} F_GETFL ()\n\
Return the value required to request that @code{fcntl} to return the\n\
file status flags.\n\
@seealso{fcntl, F_DUPFD, F_GETFD, F_SETFD, F_SETFL}\n\
@end deftypefn")
{
  return const_value (args, F_GETFL);
}
#endif

#if defined (F_SETFD)
DEFUNX ("F_SETFD", FF_SETFD, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} F_SETFD ()\n\
Return the value required to request that @code{fcntl} to set the file\n\
descriptor flags.\n\
@seealso{fcntl, F_DUPFD, F_GETFD, F_GETFL, F_SETFL}\n\
@end deftypefn")
{
  return const_value (args, F_SETFD);
}
#endif

#if defined (F_SETFL)
DEFUNX ("F_SETFL", FF_SETFL, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} F_SETFL ()\n\
Return the value required to request that @code{fcntl} to set the file\n\
status flags.\n\
@seealso{fcntl, F_DUPFD, F_GETFD, F_GETFL, F_SETFD}\n\
@end deftypefn")
{
  return const_value (args, F_SETFL);
}
#endif

#if defined (O_APPEND)
DEFUNX ("O_APPEND", FO_APPEND, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_APPEND ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate each write operation appends,\n\
or that may be passed to @code{fcntl} to set the write mode to append.\\n\
@seealso{fcntl, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_APPEND);
}
#endif

#if defined (O_ASYNC)
DEFUNX ("O_ASYNC", FO_ASYNC, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_ASYNC ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate asynchronous I/O.\n\
@seealso{fcntl, O_APPEND, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_ASYNC);
}
#endif

#if defined (O_CREAT)
DEFUNX ("O_CREAT", FO_CREAT, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_CREAT ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that a file should be\n\
created if it does not exist.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_CREAT);
}
#endif

#if defined (O_EXCL)
DEFUNX ("O_EXCL", FO_EXCL, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_EXCL ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that file locking is used.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_EXCL);
}
#endif

#if defined (O_NONBLOCK)
DEFUNX ("O_NONBLOCK", FO_NONBLOCK, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_NONBLOCK ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that non-blocking I/O is in use,\n\
or that may be passsed to @code{fcntl} to set non-blocking I/O.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_NONBLOCK);
}
#endif

#if defined (O_RDONLY)
DEFUNX ("O_RDONLY", FO_RDONLY, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_RDONLY ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that a file is open for\n\
reading only.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDWR, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_RDONLY);
}
#endif

#if defined (O_RDWR)
DEFUNX ("O_RDWR", FO_RDWR, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_RDWR ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that a file is open for both\n\
reading and writing.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_SYNC, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_RDWR);
}
#endif

#if defined (O_SYNC)
DEFUNX ("O_SYNC", FO_SYNC, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_SYNC ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that a file is open for\n\
synchronous I/O.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_TRUNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_SYNC);
}
#endif

#if defined (O_TRUNC)
DEFUNX ("O_TRUNC", FO_TRUNC, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Variable} O_TRUNC ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that if file exists, it should\n\
be truncated when writing.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_WRONLY}\n\
@end deftypefn")
{
  return const_value (args, O_TRUNC);
}
#endif

#if defined (O_WRONLY)
DEFUNX ("O_WRONLY", FO_WRONLY, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} O_WRONLY ()\n\
Return the numerical value of the file status flag that may be\n\
returned by @code{fcntl} to indicate that a file is open for\n\
writing only.\n\
@seealso{fcntl, O_APPEND, O_ASYNC, O_CREAT, O_EXCL, O_NONBLOCK, O_RDONLY, O_RDWR, O_SYNC, O_TRUNC}\n\
@end deftypefn")
{
  return const_value (args, O_WRONLY);
}
#endif

#if !defined (WNOHANG)
#define WNOHANG 0
#endif

DEFUNX ("WNOHANG", FWNOHANG, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WNOHANG ()\n\
Return the numerical value of the option argument that may be\n\
passed to @code{waitpid} to indicate that it should return its\n\
status immediately instead of waiting for a process to exit.\n\
@seealso{waitpid, WUNTRACED, WCONTINUE}\n\
@end deftypefn")
{
  return const_value (args, WNOHANG);
}

#if !defined (WUNTRACED)
#define WUNTRACED 0
#endif

DEFUNX ("WUNTRACED", FWUNTRACED, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WUNTRACED ()\n\
Return the numerical value of the option argument that may be\n\
passed to @code{waitpid} to indicate that it should also return\n\
if the child process has stopped but is not traced via the\n\
@code{ptrace} system call\n\
@seealso{waitpid, WNOHANG, WCONTINUE}\n\
@end deftypefn")
{
  return const_value (args, WUNTRACED);
}

#if !defined (WCONTINUE)
#define WCONTINUE 0
#endif

DEFUNX ("WCONTINUE", FWCONTINUE, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} WCONTINUE ()\n\
Return the numerical value of the option argument that may be\n\
passed to @code{waitpid} to indicate that it should also return\n\
if a stopped child has been resumed by delivery of a @code{SIGCONT}\n\
signal.\n\
@seealso{waitpid, WNOHANG, WUNTRACED}\n\
@end deftypefn")
{
  return const_value (args, WCONTINUE);
}