-# signbit.m4 serial 9
-dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
+# signbit.m4 serial 13
+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.
AC_DEFUN([gl_SIGNBIT],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([for signbit macro], [gl_cv_func_signbit],
[
AC_RUN_IFELSE(
])],
[gl_cv_func_signbit=yes],
[gl_cv_func_signbit=no],
- [gl_cv_func_signbit="guessing no"])
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_signbit="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_signbit="guessing no" ;;
+ esac
+ ])
])
dnl GCC 4.0 and newer provides three built-ins for signbit.
dnl They can be used without warnings, also in C++, regardless of <math.h>.
])],
[gl_cv_func_signbit_gcc=yes],
[gl_cv_func_signbit_gcc=no],
- [gl_cv_func_signbit_gcc="guessing no"])
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_signbit_gcc="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_signbit_gcc="guessing no" ;;
+ esac
+ ])
])
dnl Use the compiler built-ins whenever possible, because they are more
dnl efficient than the system library functions (if they exist).
- if test "$gl_cv_func_signbit_gcc" = yes; then
- REPLACE_SIGNBIT_USING_GCC=1
- else
- if test "$gl_cv_func_signbit" != yes; then
- REPLACE_SIGNBIT=1
- AC_LIBOBJ([signbitf])
- AC_LIBOBJ([signbitd])
- AC_LIBOBJ([signbitl])
- gl_FLOAT_SIGN_LOCATION
- gl_DOUBLE_SIGN_LOCATION
- gl_LONG_DOUBLE_SIGN_LOCATION
- if test "$gl_cv_cc_float_signbit" = unknown; then
- dnl Test whether copysignf() is declared.
- AC_CHECK_DECLS([copysignf], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysignf" = yes; then
- dnl Test whether copysignf() can be used without libm.
- AC_CACHE_CHECK([whether copysignf can be used without linking with libm],
- [gl_cv_func_copysignf_no_libm],
- [
- 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 $gl_cv_func_copysignf_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
- [Define if the copysignf function is declared in <math.h> and available in libc.])
+ case "$gl_cv_func_signbit_gcc" in
+ *yes)
+ REPLACE_SIGNBIT_USING_GCC=1
+ ;;
+ *)
+ case "$gl_cv_func_signbit" in
+ *yes) ;;
+ *)
+ dnl REPLACE_SIGNBIT=1 makes sure the signbit[fdl] functions get built.
+ REPLACE_SIGNBIT=1
+ gl_FLOAT_SIGN_LOCATION
+ gl_DOUBLE_SIGN_LOCATION
+ gl_LONG_DOUBLE_SIGN_LOCATION
+ if test "$gl_cv_cc_float_signbit" = unknown; then
+ dnl Test whether copysignf() is declared.
+ AC_CHECK_DECLS([copysignf], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysignf" = yes; then
+ dnl Test whether copysignf() can be used without libm.
+ AC_CACHE_CHECK([whether copysignf can be used without linking with libm],
+ [gl_cv_func_copysignf_no_libm],
+ [
+ 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 $gl_cv_func_copysignf_no_libm = yes; then
+ AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
+ [Define if the copysignf function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- if test "$gl_cv_cc_double_signbit" = unknown; then
- dnl Test whether copysign() is declared.
- AC_CHECK_DECLS([copysign], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysign" = yes; then
- dnl Test whether copysign() can be used without libm.
- AC_CACHE_CHECK([whether copysign can be used without linking with libm],
- [gl_cv_func_copysign_no_libm],
- [
- 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 $gl_cv_func_copysign_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
- [Define if the copysign function is declared in <math.h> and available in libc.])
+ if test "$gl_cv_cc_double_signbit" = unknown; then
+ dnl Test whether copysign() is declared.
+ AC_CHECK_DECLS([copysign], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysign" = yes; then
+ dnl Test whether copysign() can be used without libm.
+ AC_CACHE_CHECK([whether copysign can be used without linking with libm],
+ [gl_cv_func_copysign_no_libm],
+ [
+ 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 $gl_cv_func_copysign_no_libm = yes; then
+ AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
+ [Define if the copysign function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- if test "$gl_cv_cc_long_double_signbit" = unknown; then
- dnl Test whether copysignl() is declared.
- AC_CHECK_DECLS([copysignl], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysignl" = yes; then
- dnl Test whether copysignl() can be used without libm.
- AC_CACHE_CHECK([whether copysignl can be used without linking with libm],
- [gl_cv_func_copysignl_no_libm],
- [
- 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 $gl_cv_func_copysignl_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], [1],
- [Define if the copysignl function is declared in <math.h> and available in libc.])
+ if test "$gl_cv_cc_long_double_signbit" = unknown; then
+ dnl Test whether copysignl() is declared.
+ AC_CHECK_DECLS([copysignl], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysignl" = yes; then
+ dnl Test whether copysignl() can be used without libm.
+ AC_CACHE_CHECK([whether copysignl can be used without linking with libm],
+ [gl_cv_func_copysignl_no_libm],
+ [
+ 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],
+ [Define if the copysignl function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- fi
- fi
+ ;;
+ esac
+ ;;
+ esac
])
AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [[
/* 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. */
+ cross-compiling to PowerPC on Mac OS X 10.5. */
long double p0l = 0.0L;
#if defined __hpux || defined __sgi
long double m0l = -LDBL_MIN * LDBL_MIN;