fchdir: port to mingw

[gnulib.git] / m4 / frexpl.m4

diff --git a/m4/frexpl.m4 b/m4/frexpl.m4
index dad5dd7..c5da744 100644 (file)
--- a/m4/frexpl.m4
+++ b/m4/frexpl.m4
@@ -1,5 +1,5 @@
-# frexpl.m4 serial 5
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# frexpl.m4 serial 9
+dnl Copyright (C) 2007-2009 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.
@@ -48,7 +48,7 @@ AC_DEFUN([gl_FUNC_FREXPL],
     gl_func_frexpl=no
   fi
   if test $gl_func_frexpl = yes; then
-    AC_DEFINE([HAVE_FREXPL], 1,
+    AC_DEFINE([HAVE_FREXPL], [1],
       [Define if the frexpl() function is available.])
     dnl Also check whether it's declared.
     dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
@@ -84,7 +84,7 @@ AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
     REPLACE_FREXPL=1
   fi
   if test $gl_func_frexpl_no_libm = yes; then
-    AC_DEFINE([HAVE_FREXPL_IN_LIBC], 1,
+    AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
       [Define if the frexpl() function is available in libc.])
     dnl Also check whether it's declared.
     dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
@@ -95,8 +95,10 @@ AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
   fi
 ])
 
-dnl Test whether frexpl() works on finite numbers (this fails on AIX 5.1 and
-dnl on BeOS) and 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), on denormalized numbers
+dnl (this fails on MacOS X 10.5/i386), and also on infinite numbers (this
+dnl fails e.g. on IRIX 6.5 and mingw).
 AC_DEFUN([gl_FUNC_FREXPL_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -104,12 +106,18 @@ AC_DEFUN([gl_FUNC_FREXPL_WORKS],
   AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
     [
       AC_TRY_RUN([
+#include <float.h>
 #include <math.h>
+/* Override the values of <float.h>, like done in float.in.h.  */
+#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP    (-16381)
+#endif
 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;
@@ -117,6 +125,18 @@ int main()
     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
@@ -131,6 +151,21 @@ int main()
           return 1;
       }
   }
+  /* Test on denormalized numbers.  */
+  {
+    int i;
+    for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
+      ;
+    if (x > 0.0L)
+      {
+        int exp;
+        long double y = frexpl (x, &exp);
+        /* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
+           exp = -16382, y = 0.5.  On MacOS X 10.5: exp = -16384, y = 0.5.  */
+        if (exp != LDBL_MIN_EXP - 1)
+          return 1;
+      }
+  }
   /* Test on infinite numbers.  */
   x = 1.0L / 0.0L;
   {
@@ -142,8 +177,9 @@ int main()
   return 0;
 }], [gl_cv_func_frexpl_works=yes], [gl_cv_func_frexpl_works=no],
       [case "$host_os" in
-         aix* | beos* | 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
       ])
     ])