-# signbit.m4 serial 3
-dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
+# signbit.m4 serial 7
+dnl Copyright (C) 2007-2010 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_REQUIRE([gl_MATH_H_DEFAULTS])
AC_CACHE_CHECK([for signbit macro], [gl_cv_func_signbit],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#include <math.h>
/* If signbit is defined as a function, don't use it, since calling it for
'float' or 'long double' arguments would involve conversions.
#endif
#include <string.h>
]gl_SIGNBIT_TEST_PROGRAM
-, [gl_cv_func_signbit=yes], [gl_cv_func_signbit=no],
+])],
+ [gl_cv_func_signbit=yes],
+ [gl_cv_func_signbit=no],
[gl_cv_func_signbit="guessing no"])
])
dnl GCC 4.0 and newer provides three built-ins for signbit.
dnl libc.
AC_CACHE_CHECK([for signbit compiler built-ins], [gl_cv_func_signbit_gcc],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#if __GNUC__ >= 4
# define signbit(x) \
(sizeof (x) == sizeof (long double) ? __builtin_signbitl (x) : \
#endif
#include <string.h>
]gl_SIGNBIT_TEST_PROGRAM
-, [gl_cv_func_signbit_gcc=yes], [gl_cv_func_signbit_gcc=no],
+])],
+ [gl_cv_func_signbit_gcc=yes],
+ [gl_cv_func_signbit_gcc=no],
[gl_cv_func_signbit_gcc="guessing no"])
])
dnl Use the compiler built-ins whenever possible, because they are more
AC_CACHE_CHECK([whether copysignf can be used without linking with libm],
[gl_cv_func_copysignf_no_libm],
[
- AC_TRY_LINK([#include <math.h>
- float x, y;],
- [return copysignf (x, y) < 0;],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ float x, y;]],
+ [[return copysignf (x, y) < 0;]])],
[gl_cv_func_copysignf_no_libm=yes],
[gl_cv_func_copysignf_no_libm=no])
])
if test $gl_cv_func_copysignf_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], 1,
+ AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
[Define if the copysignf function is declared in <math.h> and available in libc.])
fi
fi
AC_CACHE_CHECK([whether copysign can be used without linking with libm],
[gl_cv_func_copysign_no_libm],
[
- AC_TRY_LINK([#include <math.h>
- double x, y;],
- [return copysign (x, y) < 0;],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ double x, y;]],
+ [[return copysign (x, y) < 0;]])],
[gl_cv_func_copysign_no_libm=yes],
[gl_cv_func_copysign_no_libm=no])
])
if test $gl_cv_func_copysign_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], 1,
+ AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
[Define if the copysign function is declared in <math.h> and available in libc.])
fi
fi
AC_CACHE_CHECK([whether copysignl can be used without linking with libm],
[gl_cv_func_copysignl_no_libm],
[
- AC_TRY_LINK([#include <math.h>
- long double x, y;],
- [return copysignl (x, y) < 0;],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ long double x, y;]],
+ [[return copysignl (x, y) < 0;]])],
[gl_cv_func_copysignl_no_libm=yes],
[gl_cv_func_copysignl_no_libm=no])
])
if test $gl_cv_func_copysignl_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], 1,
+ AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], [1],
[Define if the copysignl function is declared in <math.h> and available in libc.])
fi
fi
fi
])
-AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [
+AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [[
+/* Global variables.
+ Needed because GCC 4 constant-folds __builtin_signbitl (literal)
+ but cannot constant-fold __builtin_signbitl (variable). */
+float vf;
+double vd;
+long double vl;
+int main ()
+{
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+ So we use -p0f and -p0d instead. */
float p0f = 0.0f;
-float m0f = -0.0f;
+float m0f = -p0f;
double p0d = 0.0;
-double m0d = -0.0;
+double m0d = -p0d;
+/* On HP-UX 10.20, negating 0.0L does not yield -0.0L.
+ So we use another constant expression instead.
+ But that expression does not work on other platforms, such as when
+ cross-compiling to PowerPC on MacOS X 10.5. */
long double p0l = 0.0L;
-long double m0l = -0.0L;
-int main ()
-{
+#if defined __hpux || defined __sgi
+long double m0l = -LDBL_MIN * LDBL_MIN;
+#else
+long double m0l = -p0l;
+#endif
+ if (signbit (vf))
+ vf++;
{
float plus_inf = 1.0f / p0f;
float minus_inf = -1.0f / p0f;
&& signbit (minus_inf)))
return 1;
}
+ if (signbit (vd))
+ vd++;
{
double plus_inf = 1.0 / p0d;
double minus_inf = -1.0 / p0d;
&& signbit (minus_inf)))
return 1;
}
+ if (signbit (vl))
+ vl++;
{
long double plus_inf = 1.0L / p0l;
long double minus_inf = -1.0L / p0l;
}
return 0;
}
-])
+]])
AC_DEFUN([gl_FLOAT_SIGN_LOCATION],
[
AC_CACHE_CHECK([where to find the sign bit in a '$1'],
[$2],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#include <stddef.h>
#include <stdio.h>
#define NWORDS \
fprintf (fp, "word %d bit %d", (int) k, (int) i);
return (fclose (fp) != 0);
}
- ],
+ ]])],
[$2=`cat conftest.out`],
[$2="unknown"],
[