[PATCH] __cat and __unique_id in stringify.h

[PATCH] __cat and __unique_id in stringify.h

[Rusty Russell]

__cat() to paste tokens could be used in a few places, and
__unique_id() is useful for module.h.

Linus, please apply,
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

Name: Centralize token pasting and generation of unique IDs
Author: Rusty Russell
Status: Tested on 2.5.70-bk13

D: Add __cat(a,b) to implement token pasting to stringify.h.  To
D: generate unique names, __unique_id(stem) is implemented (it'd be
D: nice to have a gcc extension to give a unique identifier).  Change
D: module.h to use them.

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .26569-linux-2.5.70-bk16/include/linux/module.h .26569-linux-2.5.70-bk16.updated/include/linux/module.h
--- .26569-linux-2.5.70-bk16/include/linux/module.h	2003-06-12 09:58:02.000000000 +1000
+++ .26569-linux-2.5.70-bk16.updated/include/linux/module.h	2003-06-12 16:19:16.000000000 +1000
@@ -55,10 +55,8 @@ search_extable(const struct exception_ta
 	       unsigned long value);
 
 #ifdef MODULE
-#define ___module_cat(a,b) __mod_ ## a ## b
-#define __module_cat(a,b) ___module_cat(a,b)
 #define __MODULE_INFO(tag, name, info)					  \
-static const char __module_cat(name,__LINE__)[]				  \
+static const char __unique_id(name)[]					  \
   __attribute__((section(".modinfo"),unused)) = __stringify(tag) "=" info
 
 #define MODULE_GENERIC_TABLE(gtype,name)			\
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .26569-linux-2.5.70-bk16/include/linux/stringify.h .26569-linux-2.5.70-bk16.updated/include/linux/stringify.h
--- .26569-linux-2.5.70-bk16/include/linux/stringify.h	2003-01-02 12:25:36.000000000 +1100
+++ .26569-linux-2.5.70-bk16.updated/include/linux/stringify.h	2003-06-12 16:32:17.000000000 +1000
@@ -9,4 +9,11 @@
 #define __stringify_1(x)	#x
 #define __stringify(x)		__stringify_1(x)
 
+/* Paste two tokens together. */
+#define ___cat(a,b) a ## b
+#define __cat(a,b) ___cat(a,b)
+
+/* Try to give a unique identifier: this comes close, iff used as static. */
+#define __unique_id(stem) \
+	__cat(__cat(__uniq,stem),__cat(__LINE__,KBUILD_BASENAME))
 #endif	/* !__LINUX_STRINGIFY_H */

Re: [PATCH] __cat and __unique_id in stringify.h

[Jörn Engel]

On Thu, 12 June 2003 16:41:53 +1000, Rusty Russell wrote:
> +/* Paste two tokens together. */
> +#define ___cat(a,b) a ## b
> +#define __cat(a,b) ___cat(a,b)

It might be a bit too easy to type ___cat instead of __cat.  If you
use ___cat___ or something similar, there might be less problems
caused by typing problems.

Jörn

-- 
With a PC, I always felt limited by the software available. On Unix, 
I am limited only by my knowledge.
-- Peter J. Schoenster