-# frexp.m4 serial 9
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# frexp.m4 serial 14
+dnl Copyright (C) 2007-2012 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.
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])
])
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), 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_FUNCS_ONCE([alarm])
AC_CACHE_CHECK([whether frexp works], [gl_cv_func_frexp_works],
[
AC_RUN_IFELSE(
#include <float.h>
#include <math.h>
#include <string.h>
+#if HAVE_ALARM
+# 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_ALARM
+ /* NeXTstep 3.3 frexp() runs into an endless loop when called on an infinite
+ number. Let the test fail in this case. */
+ alarm (5);
+#endif
/* Test on denormalized numbers. */
for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
;
/* 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],