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[gnulib.git] / m4 / frexpl.m4

diff --git a/m4/frexpl.m4 b/m4/frexpl.m4
index 8832181..01cb1d9 100644 (file)
--- a/m4/frexpl.m4
+++ b/m4/frexpl.m4
@@ -1,4 +1,4 @@
-# frexpl.m4 serial 3
+# frexpl.m4 serial 6
 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,
@@ -80,6 +80,8 @@ AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
     esac
   else
     gl_func_frexpl_no_libm=no
+    dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
+    REPLACE_FREXPL=1
   fi
   if test $gl_func_frexpl_no_libm = yes; then
     AC_DEFINE([HAVE_FREXPL_IN_LIBC], 1,
@@ -93,8 +95,9 @@ AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
   fi
 ])
 
-dnl Test whether frexpl() works on finite numbers (this fails on AIX 5.1) and
-dnl also on infinite numbers (this fails e.g. on IRIX 6.5).
+dnl Test whether frexpl() works on finite numbers (this fails on
+dnl MacOS X 10.4/PowerPC, on AIX 5.1, and on BeOS) and also on infinite numbers
+dnl (this fails e.g. on IRIX 6.5 and mingw).
 AC_DEFUN([gl_FUNC_FREXPL_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -107,17 +110,43 @@ extern long double frexpl (long double, int *);
 int main()
 {
   volatile long double x;
-  /* Test on finite numbers.  */
+  /* Test on finite numbers that fails on AIX 5.1.  */
+  x = 16.0L;
   {
     int exp = -9999;
-    x = 16.0L;
     frexpl (x, &exp);
     if (exp != 5)
       return 1;
   }
+  /* Test on finite numbers that fails on MacOS X 10.4, because its frexpl
+     function returns an invalid (incorrectly normalized) value: it returns
+               y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
+     but the correct result is
+          0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 }  */
+  x = 1.01L;
+  {
+    int exp = -9999;
+    long double y = frexpl (x, &exp);
+    if (!(exp == 1 && y == 0.505L))
+      return 1;
+  }
+  /* Test on large finite numbers.  This fails on BeOS at i = 16322, while
+     LDBL_MAX_EXP = 16384.
+     In the loop end test, we test x against Infinity, rather than comparing
+     i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP.  */
+  {
+    int i;
+    for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
+      {
+        int exp = -9999;
+        frexpl (x, &exp);
+        if (exp != i)
+          return 1;
+      }
+  }
   /* Test on infinite numbers.  */
+  x = 1.0L / 0.0L;
   {
-    x = 1.0L / 0.0L;
     int exp;
     long double y = frexpl (x, &exp);
     if (y != x)
@@ -126,8 +155,9 @@ int main()
   return 0;
 }], [gl_cv_func_frexpl_works=yes], [gl_cv_func_frexpl_works=no],
       [case "$host_os" in
-         aix* | irix*) gl_cv_func_frexpl_works="guessing no";;
-         *)            gl_cv_func_frexpl_works="guessing yes";;
+         aix* | beos* | darwin* | irix* | mingw* | pw*)
+            gl_cv_func_frexpl_works="guessing no";;
+         *) gl_cv_func_frexpl_works="guessing yes";;
        esac
       ])
     ])