Dogcows Code - chaz/tar/blob - src/open3.h

   1 /* Defines for Sys V style 3-argument open call.
   2    Copyright (C) 1988 Free Software Foundation
   3
   4 This file is part of GNU Tar.
   5
   6 GNU Tar is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Tar is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Tar; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 /*
  21  * open3.h -- #defines for the various flags for the Sys V style 3-argument
  22  * open() call.  On BSD or System 5, the system already has this in an
  23  * include file.  This file is needed for V7 and MINIX systems for the
  24  * benefit of open3() in port.c, a routine that emulates the 3-argument
  25  * call using system calls available on V7/MINIX.
  26  *
  27  * This file is needed by PD tar even if we aren't using the
  28  * emulator, since the #defines for O_WRONLY, etc. are used in
  29  * a couple of places besides the open() calls, (e.g. in the assignment
  30  * to openflag in extract.c).  We just #include this rather than
  31  * #ifdef them out.
  32  *
  33  * Written 6/10/87 by rmtodd@uokmax (Richard Todd).
  34  *
  35  * The names have been changed by John Gilmore, 31 July 1987, since
  36  * Richard called it "bsdopen", and really this change was introduced in
  37  * AT&T Unix systems before BSD picked it up.
  38  */
  39
  40 /* Only one of the next three should be specified */
  41 #define O_RDONLY         0 /* only allow read */
  42 #define O_WRONLY         1 /* only allow write */
  43 #define O_RDWR           2 /* both are allowed */
  44
  45 /* The rest of these can be OR-ed in to the above. */
  46 /*
  47  * O_NDELAY isn't implemented by the emulator.  It's only useful (to tar) on
  48  * systems that have named pipes anyway; it prevents tar's hanging by
  49  * opening a named pipe.  We #ifndef it because some systems already have
  50  * it defined.
  51  */
  52 #ifndef O_NDELAY
  53 #define O_NDELAY         4 /* don't block on opening devices that would
  54                             * block on open -- ignored by emulator. */
  55 #endif
  56 #define O_CREAT          8 /* create file if needed */
  57 #define O_EXCL          16 /* file cannot already exist */
  58 #define O_TRUNC         32 /* truncate file on open */
  59 #define O_APPEND        64 /* always write at end of file -- ignored by emul */
  60
  61 #ifdef EMUL_OPEN3
  62 /*
  63  * make emulation transparent to rest of file -- redirect all open() calls
  64  * to our routine
  65  */
  66 #define open    open3
  67 #endif