view m4/intdiv0.m4 @ 17627:4d899884c95c

m4: fix gl_TIMER_TIME() detection of threads on uClibc The timer_time.m4 gl_TIMER_TIME function determines which libraries need to be linked to get access to the timer function, generally -lrt for Linux systems. On platforms where threads are used, librt typically uses thread functions from libpthread. However, the test to determine whether the platform has thread or not is incorrect: it assumes that if the C library is uClibc, then threads are not available. This is actually not true: uClibc has configurable thread support, and when thread support is available, librt calls libpthread functions. This is important when static linking is used, because otherwise only -lrt is used at link time, which fails because librt calls undefined thread functions. Both -lrt and -lpthread must be passed. This problem is fixed by making the uClibc thread detection a bit smarter, thanks to the usage of the __HAS_NO_THREADS__ macro defined in <bits/uClibc_config.h>, which itself is included by <features.h>. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Eric Blake <eblake@redhat.com>
author Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
date Sat, 22 Feb 2014 00:41:38 +0100
parents 344018b6e5d7
children
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# intdiv0.m4 serial 6 (gettext-0.18.2)
dnl Copyright (C) 2002, 2007-2008, 2010-2014 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 From Bruno Haible.

AC_DEFUN([gt_INTDIV0],
[
  AC_REQUIRE([AC_PROG_CC])dnl
  AC_REQUIRE([AC_CANONICAL_HOST])dnl

  AC_CACHE_CHECK([whether integer division by zero raises SIGFPE],
    gt_cv_int_divbyzero_sigfpe,
    [
      gt_cv_int_divbyzero_sigfpe=
changequote(,)dnl
      case "$host_os" in
        macos* | darwin[6-9]* | darwin[1-9][0-9]*)
          # On Mac OS X 10.2 or newer, just assume the same as when cross-
          # compiling. If we were to perform the real test, 1 Crash Report
          # dialog window would pop up.
          case "$host_cpu" in
            i[34567]86 | x86_64)
              gt_cv_int_divbyzero_sigfpe="guessing yes" ;;
          esac
          ;;
      esac
changequote([,])dnl
      if test -z "$gt_cv_int_divbyzero_sigfpe"; then
        AC_RUN_IFELSE(
          [AC_LANG_SOURCE([[
#include <stdlib.h>
#include <signal.h>

static void
sigfpe_handler (int sig)
{
  /* Exit with code 0 if SIGFPE, with code 1 if any other signal.  */
  exit (sig != SIGFPE);
}

int x = 1;
int y = 0;
int z;
int nan;

int main ()
{
  signal (SIGFPE, sigfpe_handler);
/* IRIX and AIX (when "xlc -qcheck" is used) yield signal SIGTRAP.  */
#if (defined (__sgi) || defined (_AIX)) && defined (SIGTRAP)
  signal (SIGTRAP, sigfpe_handler);
#endif
/* Linux/SPARC yields signal SIGILL.  */
#if defined (__sparc__) && defined (__linux__)
  signal (SIGILL, sigfpe_handler);
#endif

  z = x / y;
  nan = y / y;
  exit (2);
}
]])],
          [gt_cv_int_divbyzero_sigfpe=yes],
          [gt_cv_int_divbyzero_sigfpe=no],
          [
            # Guess based on the CPU.
changequote(,)dnl
            case "$host_cpu" in
              alpha* | i[34567]86 | x86_64 | m68k | s390*)
                gt_cv_int_divbyzero_sigfpe="guessing yes";;
              *)
                gt_cv_int_divbyzero_sigfpe="guessing no";;
            esac
changequote([,])dnl
          ])
      fi
    ])
  case "$gt_cv_int_divbyzero_sigfpe" in
    *yes) value=1;;
    *) value=0;;
  esac
  AC_DEFINE_UNQUOTED([INTDIV0_RAISES_SIGFPE], [$value],
    [Define if integer division by zero raises signal SIGFPE.])
])