io/fcntl.h

   1 /* Copyright (C) 1991,1992,1994-2001,2003,2004,2005,2006,2007
   2         Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 /*
  21  *      POSIX Standard: 6.5 File Control Operations     <fcntl.h>
  22  */
  23
  24 #ifndef _FCNTL_H
  25 #define _FCNTL_H        1
  26
  27 #include <features.h>
  28
  29 /* This must be early so <bits/fcntl.h> can define types winningly.  */
  30 __BEGIN_DECLS
  31
  32 /* Get the definitions of O_*, F_*, FD_*: all the
  33    numbers and flag bits for `open', `fcntl', et al.  */
  34 #include <bits/fcntl.h>
  35
  36 /* For XPG all symbols from <sys/stat.h> should also be available.  */
  37 #ifdef __USE_XOPEN
  38 # include <sys/stat.h>
  39 #endif
  40
  41 #ifdef  __USE_MISC
  42 # ifndef R_OK                   /* Verbatim from <unistd.h>.  Ugh.  */
  43 /* Values for the second argument to access.
  44    These may be OR'd together.  */
  45 #  define R_OK  4               /* Test for read permission.  */
  46 #  define W_OK  2               /* Test for write permission.  */
  47 #  define X_OK  1               /* Test for execute permission.  */
  48 #  define F_OK  0               /* Test for existence.  */
  49 # endif
  50 #endif /* Use misc.  */
  51
  52 /* XPG wants the following symbols.  */
  53 #ifdef __USE_XOPEN              /* <stdio.h> has the same definitions.  */
  54 # define SEEK_SET       0       /* Seek from beginning of file.  */
  55 # define SEEK_CUR       1       /* Seek from current position.  */
  56 # define SEEK_END       2       /* Seek from end of file.  */
  57 #endif  /* XPG */
  58
  59 #ifdef __USE_ATFILE
  60 # define AT_FDCWD               -100    /* Special value used to indicate
  61                                            the *at functions should use the
  62                                            current working directory. */
  63 # define AT_SYMLINK_NOFOLLOW    0x100   /* Do not follow symbolic links.  */
  64 # define AT_REMOVEDIR           0x200   /* Remove directory instead of
  65                                            unlinking file.  */
  66 # define AT_SYMLINK_FOLLOW      0x400   /* Follow symbolic links.  */
  67 # define AT_EACCESS             0x200   /* Test access permitted for
  68                                            effective IDs, not real IDs.  */
  69 #endif
  70
  71 /* Do the file control operation described by CMD on FD.
  72    The remaining arguments are interpreted depending on CMD.
  73
  74    This function is a cancellation point and therefore not marked with
  75    __THROW.  */
  76 extern int fcntl (int __fd, int __cmd, ...);
  77
  78 /* Open FILE and return a new file descriptor for it, or -1 on error.
  79    OFLAG determines the type of access used.  If O_CREAT is on OFLAG,
  80    the third argument is taken as a `mode_t', the mode of the created file.
  81
  82    This function is a cancellation point and therefore not marked with
  83    __THROW.  */
  84 #ifndef __USE_FILE_OFFSET64
  85 extern int open (__const char *__file, int __oflag, ...) __nonnull ((1));
  86 #else
  87 # ifdef __REDIRECT
  88 extern int __REDIRECT (open, (__const char *__file, int __oflag, ...), open64)
  89      __nonnull ((1));
  90 # else
  91 #  define open open64
  92 # endif
  93 #endif
  94 #ifdef __USE_LARGEFILE64
  95 extern int open64 (__const char *__file, int __oflag, ...) __nonnull ((1));
  96 #endif
  97
  98 #ifdef __USE_ATFILE
  99 /* Similar to `open' but a relative path name is interpreted relative to
 100    the directory for which FD is a descriptor.
 101
 102    NOTE: some other `openat' implementation support additional functionality
 103    through this interface, especially using the O_XATTR flag.  This is not
 104    yet supported here.
 105
 106    This function is a cancellation point and therefore not marked with
 107    __THROW.  */
 108 # ifndef __USE_FILE_OFFSET64
 109 extern int openat (int __fd, __const char *__file, int __oflag, ...)
 110      __nonnull ((2));
 111 # else
 112 #  ifdef __REDIRECT
 113 extern int __REDIRECT (openat, (int __fd, __const char *__file, int __oflag,
 114                                 ...), openat64) __nonnull ((2));
 115 #  else
 116 #   define openat openat64
 117 #  endif
 118 # endif
 119
 120 extern int openat64 (int __fd, __const char *__file, int __oflag, ...)
 121      __nonnull ((2));
 122 #endif
 123
 124 /* Create and open FILE, with mode MODE.  This takes an `int' MODE
 125    argument because that is what `mode_t' will be widened to.
 126
 127    This function is a cancellation point and therefore not marked with
 128    __THROW.  */
 129 #ifndef __USE_FILE_OFFSET64
 130 extern int creat (__const char *__file, __mode_t __mode) __nonnull ((1));
 131 #else
 132 # ifdef __REDIRECT
 133 extern int __REDIRECT (creat, (__const char *__file, __mode_t __mode),
 134                        creat64) __nonnull ((1));
 135 # else
 136 #  define creat creat64
 137 # endif
 138 #endif
 139 #ifdef __USE_LARGEFILE64
 140 extern int creat64 (__const char *__file, __mode_t __mode) __nonnull ((1));
 141 #endif
 142
 143 #if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
 144                                                && !defined __USE_POSIX))
 145 /* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
 146    files consistent.  Some systems have them there and some here, and some
 147    software depends on the macros being defined without including both.  */
 148
 149 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 150    LEN is always relative to the current file position.
 151    The CMD argument is one of the following.  */
 152
 153 # define F_ULOCK 0      /* Unlock a previously locked region.  */
 154 # define F_LOCK  1      /* Lock a region for exclusive use.  */
 155 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
 156 # define F_TEST  3      /* Test a region for other processes locks.  */
 157
 158 # ifndef __USE_FILE_OFFSET64
 159 extern int lockf (int __fd, int __cmd, __off_t __len);
 160 # else
 161 # ifdef __REDIRECT
 162 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
 163 # else
 164 #  define lockf lockf64
 165 # endif
 166 # endif
 167 # ifdef __USE_LARGEFILE64
 168 extern int lockf64 (int __fd, int __cmd, __off64_t __len);
 169 # endif
 170 #endif
 171
 172 #ifdef __USE_XOPEN2K
 173 /* Advice the system about the expected behaviour of the application with
 174    respect to the file associated with FD.  */
 175 # ifndef __USE_FILE_OFFSET64
 176 extern int posix_fadvise (int __fd, __off_t __offset, __off_t __len,
 177                           int __advise) __THROW;
 178 # else
 179 # ifdef __REDIRECT_NTH
 180 extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
 181                                            __off64_t __len, int __advise),
 182                            posix_fadvise64);
 183 # else
 184 #  define posix_fadvise posix_fadvise64
 185 # endif
 186 # endif
 187 # ifdef __USE_LARGEFILE64
 188 extern int posix_fadvise64 (int __fd, __off64_t __offset, __off64_t __len,
 189                             int __advise) __THROW;
 190 # endif
 191
 192
 193 /* Reserve storage for the data of the file associated with FD.
 194
 195    This function is a possible cancellation points and therefore not
 196    marked with __THROW.  */
 197 # ifndef __USE_FILE_OFFSET64
 198 extern int posix_fallocate (int __fd, __off_t __offset, __off_t __len);
 199 # else
 200 # ifdef __REDIRECT
 201 extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
 202                                          __off64_t __len),
 203                        posix_fallocate64);
 204 # else
 205 #  define posix_fallocate posix_fallocate64
 206 # endif
 207 # endif
 208 # ifdef __USE_LARGEFILE64
 209 extern int posix_fallocate64 (int __fd, __off64_t __offset, __off64_t __len);
 210 # endif
 211 #endif
 212
 213
 214 /* Define some inlines helping to catch common problems.  */
 215 #if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline \
 216     && defined __va_arg_pack_len
 217 # include <bits/fcntl2.h>
 218 #endif
 219
 220 __END_DECLS
 221
 222 #endif /* fcntl.h  */