Merge commit 'a39d4083cab589d7cd6a13e8a4b8db8875261d75'

[gnulib.git] / m4 / ldexpl.m4

diff --git a/m4/ldexpl.m4 b/m4/ldexpl.m4
index 0a4fe88..6959f42 100644 (file)
--- a/m4/ldexpl.m4
+++ b/m4/ldexpl.m4
@@ -1,5 +1,5 @@
-# ldexpl.m4 serial 8
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# ldexpl.m4 serial 16
+dnl Copyright (C) 2007-2014 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.
@@ -7,9 +7,16 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_LDEXPL],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+  AC_REQUIRE([gl_FUNC_ISNANL]) dnl for ISNANL_LIBM
+
+  dnl Persuade glibc <math.h> to declare ldexpl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Check whether it's declared.
-  dnl MacOS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
-  AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [#include <math.h>])
+  dnl Mac OS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
+  AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [[#include <math.h>]])
+
   LDEXPL_LIBM=
   if test $HAVE_DECL_LDEXPL = 1; then
     gl_CHECK_LDEXPL_NO_LIBM
@@ -40,7 +47,7 @@ AC_DEFUN([gl_FUNC_LDEXPL],
       LIBS="$save_LIBS"
       case "$gl_cv_func_ldexpl_works" in
         *yes) gl_func_ldexpl=yes ;;
-        *)    gl_func_ldexpl=no; REPLACE_LDEXPL=1; LDEXPL_LIBM= ;;
+        *)    gl_func_ldexpl=no; REPLACE_LDEXPL=1 ;;
       esac
     else
       gl_func_ldexpl=no
@@ -51,7 +58,13 @@ AC_DEFUN([gl_FUNC_LDEXPL],
     fi
   fi
   if test $HAVE_DECL_LDEXPL = 0 || test $gl_func_ldexpl = no; then
-    AC_LIBOBJ([ldexpl])
+    dnl Find libraries needed to link lib/ldexpl.c.
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_LDEXP])
+      LDEXPL_LIBM="$LDEXP_LIBM"
+    else
+      LDEXPL_LIBM="$ISNANL_LIBM"
+    fi
   fi
   AC_SUBST([LDEXPL_LIBM])
 ])
@@ -74,7 +87,7 @@ AC_DEFUN([gl_CHECK_LDEXPL_NO_LIBM],
 ])
 
 dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1
-dnl and MacOS X 10.4/PowerPC).
+dnl and Mac OS X 10.4/PowerPC).
 AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -84,14 +97,27 @@ AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
       AC_RUN_IFELSE(
         [AC_LANG_SOURCE([[
 #include <math.h>
-extern long double ldexpl (long double, int);
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double ldexpl (long double, int);
 int main()
 {
-  volatile long double x1 = 1.0;
-  volatile long double y1 = ldexpl (x1, -1);
-  volatile long double x2 = 1.73205L;
-  volatile long double y2 = ldexpl (x2, 0);
-  return (y1 != 0.5L) || (y2 != x2);
+  int result = 0;
+  {
+    volatile long double x = 1.0;
+    volatile long double y = ldexpl (x, -1);
+    if (y != 0.5L)
+      result |= 1;
+  }
+  {
+    volatile long double x = 1.73205L;
+    volatile long double y = ldexpl (x, 0);
+    if (y != x)
+      result |= 2;
+  }
+  return result;
 }]])],
         [gl_cv_func_ldexpl_works=yes],
         [gl_cv_func_ldexpl_works=no],