-# frexp.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# frexp.m4 serial 6
+dnl Copyright (C) 2007, 2008 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_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])
+ ])
+ if test $gl_cv_func_frexp_no_libm = yes; then
+ gl_FUNC_FREXP_WORKS
+ case "$gl_cv_func_frexp_works" in
+ *yes) gl_func_frexp_no_libm=yes ;;
+ *) gl_func_frexp_no_libm=no; REPLACE_FREXP=1 ;;
+ esac
+ else
+ gl_func_frexp_no_libm=no
+ dnl Set REPLACE_FREXP here because the system may have frexp in libm.
+ REPLACE_FREXP=1
+ fi
+ if test $gl_func_frexp_no_libm = yes; then
+ AC_DEFINE([HAVE_FREXP_IN_LIBC], 1,
+ [Define if the frexp() function is available in libc.])
+ else
+ AC_LIBOBJ([frexp])
+ fi
+])
+
dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on
-dnl NetBSD 3.0) and on infinite numbers (this fails e.g. on IRIX 6.5).
+dnl NetBSD 3.0), on infinite numbers (this fails e.g. on IRIX 6.5 and mingw),
+dnl and on negative zero (this fails e.g. on NetBSD 4.99).
AC_DEFUN([gl_FUNC_FREXP_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_TRY_RUN([
#include <float.h>
#include <math.h>
+#include <string.h>
int main()
{
int i;
volatile double x;
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+ So we use -zero instead. */
+ double zero = 0.0;
/* Test on denormalized numbers. */
for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
;
return 1;
}
/* Test on infinite numbers. */
+ x = 1.0 / 0.0;
{
- x = 1.0 / 0.0;
int exp;
double y = frexp (x, &exp);
if (y != x)
return 1;
}
+ /* Test on negative zero. */
+ x = -zero;
+ {
+ int exp;
+ double y = frexp (x, &exp);
+ if (memcmp (&y, &x, sizeof x))
+ return 1;
+ }
return 0;
}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
[case "$host_os" in
- netbsd* | irix*) gl_cv_func_frexp_works="guessing no";;
- *) gl_cv_func_frexp_works="guessing yes";;
+ netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
+ *) gl_cv_func_frexp_works="guessing yes";;
esac
])
])