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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.
40 lines
1.2 KiB
C
40 lines
1.2 KiB
C
/* Test SSIZE_MAX value and type.
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Copyright (C) 2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <limits.h>
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#include <sys/types.h>
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/* Test SSIZE_MAX has type ssize_t. */
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ssize_t x;
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extern __typeof (SSIZE_MAX) x;
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/* Test the value of SSIZE_MAX. */
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_Static_assert (SSIZE_MAX == (sizeof (ssize_t) == sizeof (int)
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? INT_MAX
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: LONG_MAX),
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"value of SSIZE_MAX");
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static int
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do_test (void)
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{
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/* This is a compilation test. */
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return 0;
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}
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#include <support/test-driver.c>
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