X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ftruncl.m4;h=c82ae11905b911190c4f424ea219d9e4821a6a70;hb=54c3ba61dfdf260865f2a6529ab414e24da17cf5;hp=e05c2d6801f00a808ae203a2101b4e462dcb65e2;hpb=dcfdd254dc3d43139dc4058521287a48753b7db3;p=gnulib.git

diff --git a/m4/truncl.m4 b/m4/truncl.m4
index e05c2d680..c82ae1190 100644
--- a/m4/truncl.m4
+++ b/m4/truncl.m4
@@ -1,5 +1,5 @@
-# truncl.m4 serial 6
-dnl Copyright (C) 2007-2008, 2010 Free Software Foundation, Inc.
+# truncl.m4 serial 11
+dnl Copyright (C) 2007-2008, 2010-2013 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.
@@ -8,11 +8,14 @@ AC_DEFUN([gl_FUNC_TRUNCL],
 [
   m4_divert_text([DEFAULTS], [gl_truncl_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
   dnl Persuade glibc <math.h> to declare truncl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Test whether truncl() is declared.
-  AC_CHECK_DECLS([truncl], , , [#include <math.h>])
+  AC_CHECK_DECLS([truncl], , , [[#include <math.h>]])
   if test "$ac_cv_have_decl_truncl" = yes; then
     dnl Test whether truncl() can be used without libm.
     TRUNCL_LIBM=?
@@ -71,6 +74,7 @@ int main()
     esac
     m4_ifdef([gl_FUNC_TRUNCL_IEEE], [
       if test $gl_truncl_required = ieee && test $REPLACE_TRUNCL = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
         AC_CACHE_CHECK([whether truncl works according to ISO C 99 with IEC 60559],
           [gl_cv_func_truncl_ieee],
           [
@@ -84,17 +88,25 @@ int main()
 #include <math.h>
 ]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
 ]gl_LONG_DOUBLE_SIGNBIT_CODE[
-int main()
+static long double dummy (long double f) { return 0; }
+int main (int argc, char *argv[])
 {
+  long double (*my_truncl) (long double) = argc ? truncl : dummy;
   /* Test whether truncl (-0.3L) is -0.0L.  */
-  if (signbitl (minus_zerol) && !signbitl (truncl (-0.3L)))
+  if (signbitl (minus_zerol) && !signbitl (my_truncl (-0.3L)))
     return 1;
   return 0;
 }
               ]])],
               [gl_cv_func_truncl_ieee=yes],
               [gl_cv_func_truncl_ieee=no],
-              [gl_cv_func_truncl_ieee="guessing no"])
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_truncl_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_truncl_ieee="guessing no" ;;
+               esac
+              ])
             LIBS="$save_LIBS"
           ])
         case "$gl_cv_func_truncl_ieee" in
@@ -107,8 +119,13 @@ int main()
     HAVE_DECL_TRUNCL=0
   fi
   if test $HAVE_DECL_TRUNCL = 0 || test $REPLACE_TRUNCL = 1; then
-    AC_LIBOBJ([truncl])
-    TRUNCL_LIBM=
+    dnl Find libraries needed to link lib/truncl.c.
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_TRUNC])
+      TRUNCL_LIBM="$TRUNC_LIBM"
+    else
+      TRUNCL_LIBM=
+    fi
   fi
   AC_SUBST([TRUNCL_LIBM])
 ])