头文件-fcntl.h

	/* Copyright (C) 1991-2020 Free Software Foundation, Inc.
	This file is part of the GNU C Library.
	The GNU C Library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.
	The GNU C Library 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
	Lesser General Public License for more details.
	You should have received a copy of the GNU Lesser General Public
	License along with the GNU C Library; if not, see
	<https://www.gnu.org/licenses/>. */
	/*
	* POSIX Standard: 6.5 File Control Operations <fcntl.h>
	*/
	#ifndef _FCNTL_H
	#define _FCNTL_H 1
	#include <features.h>
	/* This must be early so <bits/fcntl.h> can define types winningly. */
	__BEGIN_DECLS
	/* Get __mode_t, __dev_t and __off_t .*/
	#include <bits/types.h>
	/* Get the definitions of O_*, F_*, FD_*: all the
	numbers and flag bits for `open', `fcntl', et al. */
	#include <bits/fcntl.h>
	/* Detect if open needs mode as a third argument (or for openat as a fourth
	argument). */
	#ifdef __O_TMPFILE
	# define __OPEN_NEEDS_MODE(oflag) \
	(((oflag) & O_CREAT) != 0 || ((oflag) & __O_TMPFILE) == __O_TMPFILE)
	#else
	# define __OPEN_NEEDS_MODE(oflag) (((oflag) & O_CREAT) != 0)
	#endif
	/* POSIX.1-2001 specifies that these types are defined by <fcntl.h>.
	Earlier POSIX standards permitted any type ending in `_t' to be defined
	by any POSIX header, so we don't conditionalize the definitions here. */
	#ifndef __mode_t_defined
	typedef __mode_t mode_t;
	# define __mode_t_defined
	#endif
	#ifndef __off_t_defined
	# ifndef __USE_FILE_OFFSET64
	typedef __off_t off_t;
	# else
	typedef __off64_t off_t;
	# endif
	# define __off_t_defined
	#endif
	#if defined __USE_LARGEFILE64 && !defined __off64_t_defined
	typedef __off64_t off64_t;
	# define __off64_t_defined
	#endif
	#ifndef __pid_t_defined
	typedef __pid_t pid_t;
	# define __pid_t_defined
	#endif
	/* For XPG all symbols from <sys/stat.h> should also be available. */
	#ifdef __USE_XOPEN2K8
	# include <bits/types/struct_timespec.h>
	#endif
	#if defined __USE_XOPEN || defined __USE_XOPEN2K8
	# include <bits/stat.h>
	# define S_IFMT __S_IFMT
	# define S_IFDIR __S_IFDIR
	# define S_IFCHR __S_IFCHR
	# define S_IFBLK __S_IFBLK
	# define S_IFREG __S_IFREG
	# ifdef __S_IFIFO
	# define S_IFIFO __S_IFIFO
	# endif
	# ifdef __S_IFLNK
	# define S_IFLNK __S_IFLNK
	# endif
	# if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) && defined __S_IFSOCK
	# define S_IFSOCK __S_IFSOCK
	# endif
	/* Protection bits. */
	# define S_ISUID __S_ISUID /* Set user ID on execution. */
	# define S_ISGID __S_ISGID /* Set group ID on execution. */
	# if defined __USE_MISC || defined __USE_XOPEN
	/* Save swapped text after use (sticky bit). This is pretty well obsolete. */
	# define S_ISVTX __S_ISVTX
	# endif
	# define S_IRUSR __S_IREAD /* Read by owner. */
	# define S_IWUSR __S_IWRITE /* Write by owner. */
	# define S_IXUSR __S_IEXEC /* Execute by owner. */
	/* Read, write, and execute by owner. */
	# define S_IRWXU (__S_IREAD|__S_IWRITE|__S_IEXEC)
	# define S_IRGRP (S_IRUSR >> 3) /* Read by group. */
	# define S_IWGRP (S_IWUSR >> 3) /* Write by group. */
	# define S_IXGRP (S_IXUSR >> 3) /* Execute by group. */
	/* Read, write, and execute by group. */
	# define S_IRWXG (S_IRWXU >> 3)
	# define S_IROTH (S_IRGRP >> 3) /* Read by others. */
	# define S_IWOTH (S_IWGRP >> 3) /* Write by others. */
	# define S_IXOTH (S_IXGRP >> 3) /* Execute by others. */
	/* Read, write, and execute by others. */
	# define S_IRWXO (S_IRWXG >> 3)
	#endif
	#ifdef __USE_MISC
	# ifndef R_OK /* Verbatim from <unistd.h>. Ugh. */
	/* Values for the second argument to access.
	These may be OR'd together. */
	# define R_OK 4 /* Test for read permission. */
	# define W_OK 2 /* Test for write permission. */
	# define X_OK 1 /* Test for execute permission. */
	# define F_OK 0 /* Test for existence. */
	# endif
	#endif /* Use misc. */
	/* XPG wants the following symbols. <stdio.h> has the same definitions. */
	#if defined __USE_XOPEN || defined __USE_XOPEN2K8
	# define SEEK_SET 0 /* Seek from beginning of file. */
	# define SEEK_CUR 1 /* Seek from current position. */
	# define SEEK_END 2 /* Seek from end of file. */
	#endif /* XPG */
	/* Do the file control operation described by CMD on FD.
	The remaining arguments are interpreted depending on CMD.
	This function is a cancellation point and therefore not marked with
	__THROW. */
	#ifndef __USE_FILE_OFFSET64
	extern int fcntl (int __fd, int __cmd, ...);
	#else
	# ifdef __REDIRECT
	extern int __REDIRECT (fcntl, (int __fd, int __cmd, ...), fcntl64);
	# else
	# define fcntl fcntl64
	# endif
	#endif
	#ifdef __USE_LARGEFILE64
	extern int fcntl64 (int __fd, int __cmd, ...);
	#endif
	/* Open FILE and return a new file descriptor for it, or -1 on error.
	OFLAG determines the type of access used. If O_CREAT or O_TMPFILE is set
	in OFLAG, the third argument is taken as a `mode_t', the mode of the
	created file.
	This function is a cancellation point and therefore not marked with
	__THROW. */
	#ifndef __USE_FILE_OFFSET64
	extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
	#else
	# ifdef __REDIRECT
	extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
	__nonnull ((1));
	# else
	# define open open64
	# endif
	#endif
	#ifdef __USE_LARGEFILE64
	extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
	#endif
	#ifdef __USE_ATFILE
	/* Similar to `open' but a relative path name is interpreted relative to
	the directory for which FD is a descriptor.
	NOTE: some other `openat' implementation support additional functionality
	through this interface, especially using the O_XATTR flag. This is not
	yet supported here.
	This function is a cancellation point and therefore not marked with
	__THROW. */
	# ifndef __USE_FILE_OFFSET64
	extern int openat (int __fd, const char *__file, int __oflag, ...)
	__nonnull ((2));
	# else
	# ifdef __REDIRECT
	extern int __REDIRECT (openat, (int __fd, const char *__file, int __oflag,
	...), openat64) __nonnull ((2));
	# else
	# define openat openat64
	# endif
	# endif
	# ifdef __USE_LARGEFILE64
	extern int openat64 (int __fd, const char *__file, int __oflag, ...)
	__nonnull ((2));
	# endif
	#endif
	/* Create and open FILE, with mode MODE. This takes an `int' MODE
	argument because that is what `mode_t' will be widened to.
	This function is a cancellation point and therefore not marked with
	__THROW. */
	#ifndef __USE_FILE_OFFSET64
	extern int creat (const char *__file, mode_t __mode) __nonnull ((1));
	#else
	# ifdef __REDIRECT
	extern int __REDIRECT (creat, (const char *__file, mode_t __mode),
	creat64) __nonnull ((1));
	# else
	# define creat creat64
	# endif
	#endif
	#ifdef __USE_LARGEFILE64
	extern int creat64 (const char *__file, mode_t __mode) __nonnull ((1));
	#endif
	#if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
	&& !defined __USE_POSIX))
	/* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
	files consistent. Some systems have them there and some here, and some
	software depends on the macros being defined without including both. */
	/* `lockf' is a simpler interface to the locking facilities of `fcntl'.
	LEN is always relative to the current file position.
	The CMD argument is one of the following. */
	# define F_ULOCK 0 /* Unlock a previously locked region. */
	# define F_LOCK 1 /* Lock a region for exclusive use. */
	# define F_TLOCK 2 /* Test and lock a region for exclusive use. */
	# define F_TEST 3 /* Test a region for other processes locks. */
	# ifndef __USE_FILE_OFFSET64
	extern int lockf (int __fd, int __cmd, off_t __len);
	# else
	# ifdef __REDIRECT
	extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
	# else
	# define lockf lockf64
	# endif
	# endif
	# ifdef __USE_LARGEFILE64
	extern int lockf64 (int __fd, int __cmd, off64_t __len);
	# endif
	#endif
	#ifdef __USE_XOPEN2K
	/* Advice the system about the expected behaviour of the application with
	respect to the file associated with FD. */
	# ifndef __USE_FILE_OFFSET64
	extern int posix_fadvise (int __fd, off_t __offset, off_t __len,
	int __advise) __THROW;
	# else
	# ifdef __REDIRECT_NTH
	extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
	__off64_t __len, int __advise),
	posix_fadvise64);
	# else
	# define posix_fadvise posix_fadvise64
	# endif
	# endif
	# ifdef __USE_LARGEFILE64
	extern int posix_fadvise64 (int __fd, off64_t __offset, off64_t __len,
	int __advise) __THROW;
	# endif
	/* Reserve storage for the data of the file associated with FD.
	This function is a possible cancellation point and therefore not
	marked with __THROW. */
	# ifndef __USE_FILE_OFFSET64
	extern int posix_fallocate (int __fd, off_t __offset, off_t __len);
	# else
	# ifdef __REDIRECT
	extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
	__off64_t __len),
	posix_fallocate64);
	# else
	# define posix_fallocate posix_fallocate64
	# endif
	# endif
	# ifdef __USE_LARGEFILE64
	extern int posix_fallocate64 (int __fd, off64_t __offset, off64_t __len);
	# endif
	#endif
	/* Define some inlines helping to catch common problems. */
	#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function \
	&& defined __va_arg_pack_len
	# include <bits/fcntl2.h>
	#endif
	__END_DECLS
	#endif /* fcntl.h */