sysdeps/posix/dirstream.h

   1 /* Copyright (C) 1993-2020 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _DIRSTREAM_H
  19 #define _DIRSTREAM_H    1
  20
  21 #include <sys/types.h>
  22
  23 #include <libc-lock.h>
  24
  25 /* Directory stream type.
  26
  27    The miscellaneous Unix `readdir' implementations read directory data
  28    into a buffer and return `struct dirent *' pointers into it.  */
  29
  30 struct __dirstream
  31   {
  32     int fd;                     /* File descriptor.  */
  33
  34     __libc_lock_define (, lock) /* Mutex lock for this structure.  */
  35
  36     size_t allocation;          /* Space allocated for the block.  */
  37     size_t size;                /* Total valid data in the block.  */
  38     size_t offset;              /* Current offset into the block.  */
  39
  40     off_t filepos;              /* Position of next entry to read.  */
  41
  42     int errcode;                /* Delayed error code.  */
  43
  44     /* Directory block.  We must make sure that this block starts
  45        at an address that is aligned adequately enough to store
  46        dirent entries.  Using the alignment of "void *" is not
  47        sufficient because dirents on 32-bit platforms can require
  48        64-bit alignment.  We use "long double" here to be consistent
  49        with what malloc uses.  */
  50     char data[0] __attribute__ ((aligned (__alignof__ (long double))));
  51   };
  52
  53 #define _DIR_dirfd(dirp)        ((dirp)->fd)
  54
  55 #endif  /* dirstream.h */