Mercurial > gnulib
view lib/minmax.h @ 37246:5cfb3a67238d
regex: avoid glibc deadlock during configure
glibc has a known bug where certain corruptions of the heap can
cause malloc to default to printing a debug message that includes
a backtrace, but the act of getting the backtrace uses dlopen
which in turn calls into malloc, causing a recursive lock ending
in deadlock. Thus, when configure is probing for a known glibc
heap corruption bug, the overall configure would hang.
The solution suggested by glibc developers is to force malloc
to quit printing debug messages, which avoids recursive malloc.
* m4/regex.m4 (gl_REGEX): Avoid recursive malloc deadlock when
glibc bug 15078 in turn triggers bug 16159.
Reported by Michal Privoznik.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Tue, 03 Dec 2013 10:34:13 -0700 |
parents | c741bc27922a |
children | 344018b6e5d7 |
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/* MIN, MAX macros. Copyright (C) 1995, 1998, 2001, 2003, 2005, 2009-2013 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, see <http://www.gnu.org/licenses/>. */ #ifndef _MINMAX_H #define _MINMAX_H /* Note: MIN, MAX are also defined in <sys/param.h> on some systems (glibc, IRIX, HP-UX, OSF/1). Therefore you might get warnings about MIN, MAX macro redefinitions on some systems; the workaround is to #include this file as the last one among the #include list. */ /* Before we define the following symbols we get the <limits.h> file since otherwise we get redefinitions on some systems if <limits.h> is included after this file. Likewise for <sys/param.h>. If more than one of these system headers define MIN and MAX, pick just one of the headers (because the definitions most likely are the same). */ #if HAVE_MINMAX_IN_LIMITS_H # include <limits.h> #elif HAVE_MINMAX_IN_SYS_PARAM_H # include <sys/param.h> #endif /* Note: MIN and MAX should be used with two arguments of the same type. They might not return the minimum and maximum of their two arguments, if the arguments have different types or have unusual floating-point values. For example, on a typical host with 32-bit 'int', 64-bit 'long long', and 64-bit IEEE 754 'double' types: MAX (-1, 2147483648) returns 4294967295. MAX (9007199254740992.0, 9007199254740993) returns 9007199254740992.0. MAX (NaN, 0.0) returns 0.0. MAX (+0.0, -0.0) returns -0.0. and in each case the answer is in some sense bogus. */ /* MAX(a,b) returns the maximum of A and B. */ #ifndef MAX # define MAX(a,b) ((a) > (b) ? (a) : (b)) #endif /* MIN(a,b) returns the minimum of A and B. */ #ifndef MIN # define MIN(a,b) ((a) < (b) ? (a) : (b)) #endif #endif /* _MINMAX_H */