-# frexp.m4 serial 7
-dnl Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+# frexp.m4 serial 13
+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.
AC_DEFUN([gl_FUNC_FREXP],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
+ AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM])
FREXP_LIBM=
- 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 $gl_cv_func_frexp_no_libm = no; then
AC_CACHE_CHECK([whether frexp() can be used with libm],
[gl_cv_func_frexp_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
- AC_TRY_LINK([#include <math.h>
- double x;],
- [int e; return frexp (x, &e) > 0;],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ double x;]],
+ [[int e; return frexp (x, &e) > 0;]])],
[gl_cv_func_frexp_in_libm=yes],
[gl_cv_func_frexp_in_libm=no])
LIBS="$save_LIBS"
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])
])
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])
- ])
+ AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM])
if test $gl_cv_func_frexp_no_libm = yes; then
gl_FUNC_FREXP_WORKS
case "$gl_cv_func_frexp_works" in
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() can be used without linking with libm.
+dnl Set gl_cv_func_frexp_no_libm to 'yes' or 'no' accordingly.
+AC_DEFUN([gl_CHECK_FREXP_NO_LIBM],
+[
+ AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
+ [gl_cv_func_frexp_no_libm],
+ [
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#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])
+ ])
+])
+
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_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#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 MacOS 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;
-}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
- [case "$host_os" in
- netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
- *) gl_cv_func_frexp_works="guessing yes";;
- esac
- ])
+ return result;
+}]])],
+ [gl_cv_func_frexp_works=yes],
+ [gl_cv_func_frexp_works=no],
+ [case "$host_os" in
+ netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
+ *) gl_cv_func_frexp_works="guessing yes";;
+ esac
+ ])
])
])
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