X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffrexp.m4;h=ce031e701b1c81ccb0cd77ac9d89d8a31e39284f;hb=cda636671de46bd0c60641ac60d6399662d7af2c;hp=60d897b89c56c4786ee7411d0b3a71833e958a5b;hpb=6a432fe75017346930867ec2b26c675e7049f8f1;p=gnulib.git

diff --git a/m4/frexp.m4 b/m4/frexp.m4
index 60d897b89..ce031e701 100644
--- a/m4/frexp.m4
+++ b/m4/frexp.m4
@@ -1,4 +1,4 @@
-# frexp.m4 serial 1
+# frexp.m4 serial 5
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -53,10 +53,42 @@ AC_DEFUN([gl_FUNC_FREXP],
   else
     AC_LIBOBJ([frexp])
   fi
+  AC_SUBST([FREXP_LIBM])
 ])
 
-dnl Test whether frexp() works also on denormalized numbers.
-dnl This test fails e.g. on NetBSD.
+AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
+    [gl_cv_func_frexp_no_libm],
+    [
+      AC_TRY_LINK([#include <math.h>
+                   double x;],
+                  [int e; return frexp (x, &e) > 0;],
+        [gl_cv_func_frexp_no_libm=yes],
+        [gl_cv_func_frexp_no_libm=no])
+    ])
+  if test $gl_cv_func_frexp_no_libm = yes; then
+    gl_FUNC_FREXP_WORKS
+    case "$gl_cv_func_frexp_works" in
+      *yes) gl_func_frexp_no_libm=yes ;;
+      *)    gl_func_frexp_no_libm=no; REPLACE_FREXP=1 ;;
+    esac
+  else
+    gl_func_frexp_no_libm=no
+    dnl Set REPLACE_FREXP here because the system may have frexp in libm.
+    REPLACE_FREXP=1
+  fi
+  if test $gl_func_frexp_no_libm = yes; then
+    AC_DEFINE([HAVE_FREXP_IN_LIBC], 1,
+      [Define if the frexp() function is available in libc.])
+  else
+    AC_LIBOBJ([frexp])
+  fi
+])
+
+dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on
+dnl NetBSD 3.0) and on infinite numbers (this fails e.g. on IRIX 6.5 and mingw).
 AC_DEFUN([gl_FUNC_FREXP_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -70,6 +102,7 @@ int main()
 {
   int i;
   volatile double x;
+  /* Test on denormalized numbers.  */
   for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
     ;
   if (x > 0.0)
@@ -81,11 +114,19 @@ int main()
       if (y != 0.5)
         return 1;
     }
+  /* Test on infinite numbers.  */
+  x = 1.0 / 0.0;
+  {
+    int exp;
+    double y = frexp (x, &exp);
+    if (y != x)
+      return 1;
+  }
   return 0;
 }], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
       [case "$host_os" in
-         netbsd*) gl_cv_func_frexp_works="guessing no";;
-         *)       gl_cv_func_frexp_works="guessing yes";;
+         netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
+         *)                        gl_cv_func_frexp_works="guessing yes";;
        esac
       ])
     ])