install-reloc: Support multi-binary installation.

[gnulib.git] / m4 / frexp.m4

diff --git a/m4/frexp.m4 b/m4/frexp.m4
index 530fdbc..2eb98a1 100644 (file)
--- a/m4/frexp.m4
+++ b/m4/frexp.m4
@@ -1,5 +1,5 @@
-# frexp.m4 serial 9
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# frexp.m4 serial 15
+dnl Copyright (C) 2007-2013 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.
@@ -44,8 +44,6 @@ AC_DEFUN([gl_FUNC_FREXP],
   if test $gl_func_frexp = yes; then
     AC_DEFINE([HAVE_FREXP], [1],
       [Define if the frexp() function is available and works.])
-  else
-    AC_LIBOBJ([frexp])
   fi
   AC_SUBST([FREXP_LIBM])
 ])
@@ -68,8 +66,6 @@ AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
   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
 ])
 
@@ -92,11 +88,12 @@ AC_DEFUN([gl_CHECK_FREXP_NO_LIBM],
 
 dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on
 dnl NetBSD 3.0), on infinite numbers (this fails e.g. on IRIX 6.5 and mingw),
-dnl and on negative zero (this fails e.g. on NetBSD 4.99).
+dnl and on negative zero (this fails e.g. on NetBSD 4.99 and mingw).
 AC_DEFUN([gl_FUNC_FREXP_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_DECLS_ONCE([alarm])
   AC_CACHE_CHECK([whether frexp works], [gl_cv_func_frexp_works],
     [
       AC_RUN_IFELSE(
@@ -104,13 +101,36 @@ AC_DEFUN([gl_FUNC_FREXP_WORKS],
 #include <float.h>
 #include <math.h>
 #include <string.h>
+#if HAVE_DECL_ALARM
+# include <signal.h>
+# include <unistd.h>
+#endif
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+   ICC 10.0 has a bug when optimizing the expression -zero.
+   The expression -DBL_MIN * DBL_MIN does not work when cross-compiling
+   to PowerPC on Mac OS X 10.5.  */
+#if defined __hpux || defined __sgi || defined __ICC
+static double
+compute_minus_zero (void)
+{
+  return -DBL_MIN * DBL_MIN;
+}
+# define minus_zero compute_minus_zero ()
+#else
+double minus_zero = -0.0;
+#endif
 int main()
 {
+  int result = 0;
   int i;
   volatile double x;
-/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
-   So we use -zero instead.  */
   double zero = 0.0;
+#if HAVE_DECL_ALARM
+  /* NeXTstep 3.3 frexp() runs into an endless loop when called on an infinite
+     number.  Let the test fail in this case.  */
+  signal (SIGALRM, SIG_DFL);
+  alarm (5);
+#endif
   /* Test on denormalized numbers.  */
   for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
     ;
@@ -121,25 +141,25 @@ int main()
       /* On machines with IEEE754 arithmetic: x = 1.11254e-308, exp = -1022.
          On NetBSD: y = 0.75. Correct: y = 0.5.  */
       if (y != 0.5)
-        return 1;
+        result |= 1;
     }
   /* Test on infinite numbers.  */
-  x = 1.0 / 0.0;
+  x = 1.0 / zero;
   {
     int exp;
     double y = frexp (x, &exp);
     if (y != x)
-      return 1;
+      result |= 2;
   }
   /* Test on negative zero.  */
-  x = -zero;
+  x = minus_zero;
   {
     int exp;
     double y = frexp (x, &exp);
     if (memcmp (&y, &x, sizeof x))
-      return 1;
+      result |= 4;
   }
-  return 0;
+  return result;
 }]])],
         [gl_cv_func_frexp_works=yes],
         [gl_cv_func_frexp_works=no],