X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Flogf.m4;h=87876cec5969d86569122faadb845b78e4b3b2ed;hb=5191b3546cfb6c163228c23f214e325ddf60d46f;hp=0e4fa5da63ed4971990bd512cf859d2e8ea18c35;hpb=7073cb033569232bd515271e99c5c7cba4ffbdf5;p=gnulib.git

diff --git a/m4/logf.m4 b/m4/logf.m4
index 0e4fa5da6..87876cec5 100644
--- a/m4/logf.m4
+++ b/m4/logf.m4
@@ -1,11 +1,12 @@
-# logf.m4 serial 3
-dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
+# logf.m4 serial 6
+dnl Copyright (C) 2011-2013 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.
 
 AC_DEFUN([gl_FUNC_LOGF],
 [
+  m4_divert_text([DEFAULTS], [gl_logf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_FUNC_LOG])
 
@@ -20,6 +21,7 @@ AC_DEFUN([gl_FUNC_LOGF],
   LIBS="$save_LIBS"
   if test $ac_cv_func_logf = yes; then
     LOGF_LIBM="$LOG_LIBM"
+
     save_LIBS="$LIBS"
     LIBS="$LIBS $LOGF_LIBM"
     gl_FUNC_LOGF_WORKS
@@ -28,6 +30,58 @@ AC_DEFUN([gl_FUNC_LOGF],
       *yes) ;;
       *) REPLACE_LOGF=1 ;;
     esac
+
+    m4_ifdef([gl_FUNC_LOGF_IEEE], [
+      if test $gl_logf_required = ieee && test $REPLACE_LOGF = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+        AC_CACHE_CHECK([whether logf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_logf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $LOGF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+/* Compare two numbers with ==.
+   This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+   'x == x' test.  */
+static int
+numeric_equal (float x, float y)
+{
+  return x == y;
+}
+static float dummy (float x) { return 0; }
+int main (int argc, char *argv[])
+{
+  float (*my_logf) (float) = argc ? logf : dummy;
+  /* Test logf(negative).
+     This test fails on NetBSD 5.1.  */
+  float y = my_logf (-1.0f);
+  if (numeric_equal (y, y))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_logf_ieee=yes],
+              [gl_cv_func_logf_ieee=no],
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_logf_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_logf_ieee="guessing no" ;;
+               esac
+              ])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_logf_ieee" in
+          *yes) ;;
+          *) REPLACE_LOGF=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_LOGF=0
   fi