X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=include%2Fsymcat.h;h=03a12921042e55db76de39baa0dbd700dcadbb25;hb=9640c8e1ecf6463ed87865cbe14007381ace9862;hp=3e27162b26490ea46e72ad225fa667ee394af7c3;hpb=568913d8e0ba435e63626a6009c79daccee35bbd;p=pf3gnuchains%2Fgcc-fork.git

diff --git a/include/symcat.h b/include/symcat.h
index 3e27162b264..03a12921042 100644
--- a/include/symcat.h
+++ b/include/symcat.h
@@ -14,17 +14,21 @@
  
    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
-   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 #ifndef SYM_CAT_H
 #define SYM_CAT_H
 
-#if defined (__STDC__) || defined (ALMOST_STDC)
+#if defined (__STDC__) || defined (ALMOST_STDC) || defined (HAVE_STRINGIZE)
 #define CONCAT2(a,b)	 a##b
 #define CONCAT3(a,b,c)	 a##b##c
 #define CONCAT4(a,b,c,d) a##b##c##d
 #define STRINGX(s) #s
 #else
+/* Note one should never pass extra whitespace to the CONCATn macros,
+   e.g. CONCAT2(foo, bar) because traditonal C will keep the space between
+   the two labels instead of concatenating them.  Instead, make sure to
+   write CONCAT2(foo,bar).  */
 #define CONCAT2(a,b)	 a/**/b
 #define CONCAT3(a,b,c)	 a/**/b/**/c
 #define CONCAT4(a,b,c,d) a/**/b/**/c/**/d
@@ -35,6 +39,11 @@
 #define XCONCAT3(a,b,c)   CONCAT3(a,b,c)
 #define XCONCAT4(a,b,c,d) CONCAT4(a,b,c,d)
 
+/* Note the layer of indirection here is typically used to allow
+   stringification of the expansion of macros.  I.e. "#define foo
+   bar", "XSTRING(foo)", to yield "bar".  Be aware that this only
+   works for __STDC__, not for traditional C which will still resolve
+   to "foo".  */
 #define XSTRING(s) STRINGX(s) 
 
-#endif SYM_CAT_H
+#endif /* SYM_CAT_H */