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emacs/lib/pathmax.h
2022-01-01 02:45:51 -05:00

84 lines
2.9 KiB
C

/* Define PATH_MAX somehow. Requires sys/types.h.
Copyright (C) 1992, 1999, 2001, 2003, 2005, 2009-2022 Free Software
Foundation, Inc.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#ifndef _PATHMAX_H
# define _PATHMAX_H
/* POSIX:2008 defines PATH_MAX to be the maximum number of bytes in a filename,
including the terminating NUL byte.
<https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html>
PATH_MAX is not defined on systems which have no limit on filename length,
such as GNU/Hurd.
This file does *not* define PATH_MAX always. Programs that use this file
can handle the GNU/Hurd case in several ways:
- Either with a package-wide handling, or with a per-file handling,
- Either through a
#ifdef PATH_MAX
or through a fallback like
#ifndef PATH_MAX
# define PATH_MAX 8192
#endif
or through a fallback like
#ifndef PATH_MAX
# define PATH_MAX pathconf ("/", _PC_PATH_MAX)
#endif
*/
# include <unistd.h>
# include <limits.h>
# ifndef _POSIX_PATH_MAX
# define _POSIX_PATH_MAX 256
# endif
/* Don't include sys/param.h if it already has been. */
# if defined HAVE_SYS_PARAM_H && !defined PATH_MAX && !defined MAXPATHLEN
# include <sys/param.h>
# endif
# if !defined PATH_MAX && defined MAXPATHLEN
# define PATH_MAX MAXPATHLEN
# endif
# ifdef __hpux
/* On HP-UX, PATH_MAX designates the maximum number of bytes in a filename,
*not* including the terminating NUL byte, and is set to 1023.
Additionally, when _XOPEN_SOURCE is defined to 500 or more, PATH_MAX is
not defined at all any more. */
# undef PATH_MAX
# define PATH_MAX 1024
# endif
# if defined _WIN32 && ! defined __CYGWIN__
/* The page "Naming Files, Paths, and Namespaces" on msdn.microsoft.com,
section "Maximum Path Length Limitation",
<https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file#maximum-path-length-limitation>
explains that the maximum size of a filename, including the terminating
NUL byte, is 260 = 3 + 256 + 1.
This is the same value as
- FILENAME_MAX in <stdio.h>,
- _MAX_PATH in <stdlib.h>,
- MAX_PATH in <windef.h>.
Undefine the original value, because mingw's <limits.h> gets it wrong. */
# undef PATH_MAX
# define PATH_MAX 260
# endif
#endif /* _PATHMAX_H */