view m4/va-args.m4 @ 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
line wrap: on
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# va-args.m4 serial 1
dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

dnl Test for variadic macro support.
dnl Define HAVE_VA_ARGS if macros can use __VA_ARGS__.
AC_DEFUN([gl_VA_ARGS],
[
  AC_CACHE_CHECK([whether the preprocessor allows variadic macros],
    [gl_cv_c_va_args],
    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
       #include <stdio.h>
       #define a(func, arg, ...) func (arg, __VA_ARGS__)
       #define b(...) a (__VA_ARGS__)
      ]], [[b (printf, "%s", "test");]])],
      [gl_cv_c_va_args=yes], [gl_cv_c_va_args=no])
    ])
  if test $gl_cv_c_va_args = yes; then
    AC_DEFINE([HAVE_VA_ARGS], [1],
      [Define to 1 if the preprocessor supports variadic macros and
       __VA_ARGS__.])
  fi
])