From 12eef17ca76576859dbf462f2e4a3f940f3698ae Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Mon, 12 Jul 2010 23:36:34 +0200
Subject: [PATCH] Unify tests that set gl_cv_func_ldexp_no_libm.

---
 ChangeLog      |  9 +++++++++
 m4/ldexp.m4    | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 m4/strtod.m4   | 14 ++------------
 modules/ldexp  |  4 ++--
 modules/strtod |  1 +
 5 files changed, 68 insertions(+), 14 deletions(-)
 create mode 100644 m4/ldexp.m4

diff --git a/ChangeLog b/ChangeLog
index c3f530b5d..234af7425 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2010-07-12  Bruno Haible  <bruno@clisp.org>
 
+	Unify tests that set gl_cv_func_ldexp_no_libm.
+	* m4/ldexp.m4: New file, based on m4/mathfunc.m4.
+	* m4/strtod.m4 (gl_PREREQ_STRTOD): Require gl_CHECK_LDEXP_NO_LIBM.
+	* modules/ldexp (Files): Remove m4/mathfunc.m4. Add m4/ldexp.m4.
+	(configure.ac): Simply invoke gl_FUNC_LDEXP.
+	* modules/strtod (Files): Add m4/ldexp.m4.
+
+2010-07-12  Bruno Haible  <bruno@clisp.org>
+
 	Unify tests that set gl_cv_func_frexpl_no_libm.
 	* m4/frexpl.m4 (gl_CHECK_FREXPL_NO_LIBM): New macro, extracted from
 	gl_FUNC_FREXPL_NO_LIBM.
diff --git a/m4/ldexp.m4 b/m4/ldexp.m4
new file mode 100644
index 000000000..7484cb7e3
--- /dev/null
+++ b/m4/ldexp.m4
@@ -0,0 +1,54 @@
+# ldexp.m4 serial 1
+dnl Copyright (C) 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_DEFUN([gl_FUNC_LDEXP],
+[
+  AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM])
+  LDEXP_LIBM=
+  if test $gl_cv_func_ldexp_no_libm = no; then
+    AC_CACHE_CHECK([whether ldexp() can be used with libm],
+      [gl_cv_func_ldexp_in_libm],
+      [
+        save_LIBS="$LIBS"
+        LIBS="$LIBS -lm"
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES
+                             # define __NO_MATH_INLINES 1 /* for glibc */
+                             #endif
+                             #include <math.h>
+                             double (*funcptr) (double, int) = ldexp;
+                             double x;]],
+                           [[return ldexp (x, -1) > 0;]])],
+          [gl_cv_func_ldexp_in_libm=yes],
+          [gl_cv_func_ldexp_in_libm=no])
+        LIBS="$save_LIBS"
+      ])
+    if test $gl_cv_func_ldexp_in_libm = yes; then
+      LDEXP_LIBM=-lm
+    fi
+  fi
+  AC_SUBST([LDEXP_LIBM])
+])
+
+dnl Test whether ldexp() can be used without linking with libm.
+dnl Set gl_cv_func_ldexp_no_libm to 'yes' or 'no' accordingly.
+AC_DEFUN([gl_CHECK_LDEXP_NO_LIBM],
+[
+  AC_CACHE_CHECK([whether ldexp() can be used without linking with libm],
+    [gl_cv_func_ldexp_no_libm],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES
+                           # define __NO_MATH_INLINES 1 /* for glibc */
+                           #endif
+                           #include <math.h>
+                           double (*funcptr) (double, int) = ldexp;
+                           double x;]],
+                         [[return ldexp (x, -1) > 0;]])],
+        [gl_cv_func_ldexp_no_libm=yes],
+        [gl_cv_func_ldexp_no_libm=no])
+    ])
+])
diff --git a/m4/strtod.m4 b/m4/strtod.m4
index 05d36bd4b..8f90ed790 100644
--- a/m4/strtod.m4
+++ b/m4/strtod.m4
@@ -1,4 +1,4 @@
-# strtod.m4 serial 15
+# strtod.m4 serial 16
 dnl Copyright (C) 2002-2003, 2006-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -119,18 +119,8 @@ numeric_equal (double x, double y)
 ])
 
 # Prerequisites of lib/strtod.c.
-# FIXME: This implementation is a copy of printf-frexp.m4 and should be shared.
 AC_DEFUN([gl_PREREQ_STRTOD], [
-  AC_CACHE_CHECK([whether ldexp can be used without linking with libm],
-    [gl_cv_func_ldexp_no_libm],
-    [
-      AC_TRY_LINK([#include <math.h>
-                   double x;
-                   int y;],
-                  [return ldexp (x, y) < 1;],
-        [gl_cv_func_ldexp_no_libm=yes],
-        [gl_cv_func_ldexp_no_libm=no])
-    ])
+  AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM])
   if test $gl_cv_func_ldexp_no_libm = yes; then
     AC_DEFINE([HAVE_LDEXP_IN_LIBC], [1],
       [Define if the ldexp function is available in libc.])
diff --git a/modules/ldexp b/modules/ldexp
index 20818eded..025d9817f 100644
--- a/modules/ldexp
+++ b/modules/ldexp
@@ -2,12 +2,12 @@ Description:
 ldexp() function: multiply a 'double' by a power of 2.
 
 Files:
-m4/mathfunc.m4
+m4/ldexp.m4
 
 Depends-on:
 
 configure.ac:
-gl_MATHFUNC([ldexp], [double], [(double, int)])
+gl_FUNC_LDEXP
 
 Makefile.am:
 
diff --git a/modules/strtod b/modules/strtod
index d4f64c13d..056ff4263 100644
--- a/modules/strtod
+++ b/modules/strtod
@@ -4,6 +4,7 @@ strtod() function: convert string to 'double'.
 Files:
 lib/strtod.c
 m4/strtod.m4
+m4/ldexp.m4
 
 Depends-on:
 c-ctype
-- 
2.11.0