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glibc/posix/bits/posix1_lim.h
Joseph Myers 625fb764b4 Correct type of SSIZE_MAX for 32-bit (bug 13575). 
Bug 13575 reports that SSIZE_MAX is wrongly defined as LONG_MAX on
32-bit systems where ssize_t is defined as int (which is most 32-bit
systems supported by glibc).

This patch fixes the definition, using a conditional on
__WORDSIZE32_SIZE_ULONG to determine the appropriate type in the
32-bit case.  Formally ssize_t need not be the signed type
corresponding to size_t, but as it is for all current glibc
configurations, there is no need for a new macro different from the
one used for defining SIZE_MAX.  A testcase is added for both the type
and the value of SSIZE_MAX.

There is a relevant peculiarity in
sysdeps/unix/sysv/linux/s390/bits/typesizes.h:

/* Compatibility with g++ 2.95.x.  */
/* size_t is unsigned long int on s390 -m31.  */

This has the effect that for GCC 2 for s390, ssize_t does not match
__WORDSIZE32_SIZE_ULONG.  I don't think such a conditional on the GCC
version makes sense - to have a well-defined ABI, the choices of
standard types should not depend on the GCC version.  It's also the
case that upstream GCC 2.95 did not support s390, and glibc headers
don't in general try to support past development GCC versions - only
actual releases and current mainline development.  But whether or not
that GCC 2 case should be removed (with or without a NEWS entry for
such a change), this patch does not result in any changes for s390;
the value is always still LONG_MAX in the s390 case because
__WORDSIZE32_SIZE_ULONG is always defined for 32-bit s390.  I don't
think any such oddity in code only active for unofficial or unreleased
old compiler versions should block closing the present bug as fixed
once this patch is in.

Tested for x86_64 and x86, and with build-many-glibcs.py.

	[BZ #13575]
	* posix/bits/posix1_lim.h: Include <bits/wordsize.h>.
	[!SSIZE_MAX && !(__WORDSIZE == 64 || __WORDSIZE32_SIZE_ULONG)]
	(SSIZE_MAX): Define to INT_MAX.
	* posix/test-ssize-max.c: New file.
	* posix/Makefile (tests): Add test-ssize-max.
2018-02-06 21:38:51 +00:00

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/* Copyright (C) 1991-2018 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
<http://www.gnu.org/licenses/>. */
/*
* POSIX Standard: 2.9.2 Minimum Values Added to <limits.h>
*
* Never include this file directly; use <limits.h> instead.
*/
#ifndef _BITS_POSIX1_LIM_H
#define _BITS_POSIX1_LIM_H 1
#include <bits/wordsize.h>
/* These are the standard-mandated minimum values. */
/* Minimum number of operations in one list I/O call. */
#define _POSIX_AIO_LISTIO_MAX 2
/* Minimal number of outstanding asynchronous I/O operations. */
#define _POSIX_AIO_MAX 1
/* Maximum length of arguments to `execve', including environment. */
#define _POSIX_ARG_MAX 4096
/* Maximum simultaneous processes per real user ID. */
#ifdef __USE_XOPEN2K
# define _POSIX_CHILD_MAX 25
#else
# define _POSIX_CHILD_MAX 6
#endif
/* Minimal number of timer expiration overruns. */
#define _POSIX_DELAYTIMER_MAX 32
/* Maximum length of a host name (not including the terminating null)
as returned from the GETHOSTNAME function. */
#define _POSIX_HOST_NAME_MAX 255
/* Maximum link count of a file. */
#define _POSIX_LINK_MAX 8
/* Maximum length of login name. */
#define _POSIX_LOGIN_NAME_MAX 9
/* Number of bytes in a terminal canonical input queue. */
#define _POSIX_MAX_CANON 255
/* Number of bytes for which space will be
available in a terminal input queue. */
#define _POSIX_MAX_INPUT 255
/* Maximum number of message queues open for a process. */
#define _POSIX_MQ_OPEN_MAX 8
/* Maximum number of supported message priorities. */
#define _POSIX_MQ_PRIO_MAX 32
/* Number of bytes in a filename. */
#define _POSIX_NAME_MAX 14
/* Number of simultaneous supplementary group IDs per process. */
#ifdef __USE_XOPEN2K
# define _POSIX_NGROUPS_MAX 8
#else
# define _POSIX_NGROUPS_MAX 0
#endif
/* Number of files one process can have open at once. */
#ifdef __USE_XOPEN2K
# define _POSIX_OPEN_MAX 20
#else
# define _POSIX_OPEN_MAX 16
#endif
#if !defined __USE_XOPEN2K || defined __USE_GNU
/* Number of descriptors that a process may examine with `pselect' or
`select'. */
# define _POSIX_FD_SETSIZE _POSIX_OPEN_MAX
#endif
/* Number of bytes in a pathname. */
#define _POSIX_PATH_MAX 256
/* Number of bytes than can be written atomically to a pipe. */
#define _POSIX_PIPE_BUF 512
/* The number of repeated occurrences of a BRE permitted by the
REGEXEC and REGCOMP functions when using the interval notation. */
#define _POSIX_RE_DUP_MAX 255
/* Minimal number of realtime signals reserved for the application. */
#define _POSIX_RTSIG_MAX 8
/* Number of semaphores a process can have. */
#define _POSIX_SEM_NSEMS_MAX 256
/* Maximal value of a semaphore. */
#define _POSIX_SEM_VALUE_MAX 32767
/* Number of pending realtime signals. */
#define _POSIX_SIGQUEUE_MAX 32
/* Largest value of a `ssize_t'. */
#define _POSIX_SSIZE_MAX 32767
/* Number of streams a process can have open at once. */
#define _POSIX_STREAM_MAX 8
/* The number of bytes in a symbolic link. */
#define _POSIX_SYMLINK_MAX 255
/* The number of symbolic links that can be traversed in the
resolution of a pathname in the absence of a loop. */
#define _POSIX_SYMLOOP_MAX 8
/* Number of timer for a process. */
#define _POSIX_TIMER_MAX 32
/* Maximum number of characters in a tty name. */
#define _POSIX_TTY_NAME_MAX 9
/* Maximum length of a timezone name (element of `tzname'). */
#ifdef __USE_XOPEN2K
# define _POSIX_TZNAME_MAX 6
#else
# define _POSIX_TZNAME_MAX 3
#endif
#if !defined __USE_XOPEN2K || defined __USE_GNU
/* Maximum number of connections that can be queued on a socket. */
# define _POSIX_QLIMIT 1
/* Maximum number of bytes that can be buffered on a socket for send
or receive. */
# define _POSIX_HIWAT _POSIX_PIPE_BUF
/* Maximum number of elements in an `iovec' array. */
# define _POSIX_UIO_MAXIOV 16
#endif
/* Maximum clock resolution in nanoseconds. */
#define _POSIX_CLOCKRES_MIN 20000000
/* Get the implementation-specific values for the above. */
#include <bits/local_lim.h>
#ifndef SSIZE_MAX
/* ssize_t is not formally required to be the signed type
corresponding to size_t, but it is for all configurations supported
by glibc. */
# if __WORDSIZE == 64 || __WORDSIZE32_SIZE_ULONG
# define SSIZE_MAX LONG_MAX
# else
# define SSIZE_MAX INT_MAX
# endif
#endif
/* This value is a guaranteed minimum maximum.
The current maximum can be got from `sysconf'. */
#ifndef NGROUPS_MAX
# define NGROUPS_MAX 8
#endif
#endif /* bits/posix1_lim.h */
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