lib/pathmax.h

   1 /* Define PATH_MAX somehow.  Requires sys/types.h.
   2    Copyright (C) 1992, 1999, 2001, 2003, 2005, 2009-2024 Free Software
   3    Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _PATHMAX_H
  19 # define _PATHMAX_H
  20
  21 /* POSIX:2008 defines PATH_MAX to be the maximum number of bytes in a filename,
  22    including the terminating NUL byte.
  23    <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html>
  24    PATH_MAX is not defined on systems which have no limit on filename length,
  25    such as GNU/Hurd.
  26
  27    This file does *not* define PATH_MAX always.  Programs that use this file
  28    can handle the GNU/Hurd case in several ways:
  29      - Either with a package-wide handling, or with a per-file handling,
  30      - Either through a
  31          #ifdef PATH_MAX
  32        or through a fallback like
  33          #ifndef PATH_MAX
  34          # define PATH_MAX 8192
  35          #endif
  36        or through a fallback like
  37          #ifndef PATH_MAX
  38          # define PATH_MAX pathconf ("/", _PC_PATH_MAX)
  39          #endif
  40  */
  41
  42 /* This file uses HAVE_SYS_PARAM_H.  */
  43 # if !_GL_CONFIG_H_INCLUDED
  44 #  error "Please include config.h first."
  45 # endif
  46
  47 # include <unistd.h>
  48
  49 # include <limits.h>
  50
  51 # ifndef _POSIX_PATH_MAX
  52 #  define _POSIX_PATH_MAX 256
  53 # endif
  54
  55 /* Don't include sys/param.h if it already has been.  */
  56 # if defined HAVE_SYS_PARAM_H && !defined PATH_MAX && !defined MAXPATHLEN
  57 #  include <sys/param.h>
  58 # endif
  59
  60 # if !defined PATH_MAX && defined MAXPATHLEN
  61 #  define PATH_MAX MAXPATHLEN
  62 # endif
  63
  64 # ifdef __hpux
  65 /* On HP-UX, PATH_MAX designates the maximum number of bytes in a filename,
  66    *not* including the terminating NUL byte, and is set to 1023.
  67    Additionally, when _XOPEN_SOURCE is defined to 500 or more, PATH_MAX is
  68    not defined at all any more.  */
  69 #  undef PATH_MAX
  70 #  define PATH_MAX 1024
  71 # endif
  72
  73 # if defined _WIN32 && ! defined __CYGWIN__
  74 /* The page "Naming Files, Paths, and Namespaces" on msdn.microsoft.com,
  75    section "Maximum Path Length Limitation",
  76    <https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file#maximum-path-length-limitation>
  77    explains that the maximum size of a filename, including the terminating
  78    NUL byte, is 260 = 3 + 256 + 1.
  79    This is the same value as
  80      - FILENAME_MAX in <stdio.h>,
  81      - _MAX_PATH in <stdlib.h>,
  82      - MAX_PATH in <windef.h>.
  83    Undefine the original value, because mingw's <limits.h> gets it wrong.  */
  84 #  undef PATH_MAX
  85 #  define PATH_MAX 260
  86 # endif
  87
  88 #endif /* _PATHMAX_H */