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freebsd/gnu/usr.bin/tar/open3.h
1993-06-18 04:22:21 +00:00

68 lines
2.6 KiB
C

/* Defines for Sys V style 3-argument open call.
Copyright (C) 1988 Free Software Foundation
This file is part of GNU Tar.
GNU Tar 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 2, or (at your option)
any later version.
GNU Tar 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 Tar; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* open3.h -- #defines for the various flags for the Sys V style 3-argument
* open() call. On BSD or System 5, the system already has this in an
* include file. This file is needed for V7 and MINIX systems for the
* benefit of open3() in port.c, a routine that emulates the 3-argument
* call using system calls available on V7/MINIX.
*
* This file is needed by PD tar even if we aren't using the
* emulator, since the #defines for O_WRONLY, etc. are used in
* a couple of places besides the open() calls, (e.g. in the assignment
* to openflag in extract.c). We just #include this rather than
* #ifdef them out.
*
* Written 6/10/87 by rmtodd@uokmax (Richard Todd).
*
* The names have been changed by John Gilmore, 31 July 1987, since
* Richard called it "bsdopen", and really this change was introduced in
* AT&T Unix systems before BSD picked it up.
*/
/* Only one of the next three should be specified */
#define O_RDONLY 0 /* only allow read */
#define O_WRONLY 1 /* only allow write */
#define O_RDWR 2 /* both are allowed */
/* The rest of these can be OR-ed in to the above. */
/*
* O_NDELAY isn't implemented by the emulator. It's only useful (to tar) on
* systems that have named pipes anyway; it prevents tar's hanging by
* opening a named pipe. We #ifndef it because some systems already have
* it defined.
*/
#ifndef O_NDELAY
#define O_NDELAY 4 /* don't block on opening devices that would
* block on open -- ignored by emulator. */
#endif
#define O_CREAT 8 /* create file if needed */
#define O_EXCL 16 /* file cannot already exist */
#define O_TRUNC 32 /* truncate file on open */
#define O_APPEND 64 /* always write at end of file -- ignored by emul */
#ifdef EMUL_OPEN3
/*
* make emulation transparent to rest of file -- redirect all open() calls
* to our routine
*/
#define open open3
#endif