From: Arun Thomas <arun@minix3.org>
Date: Mon, 30 Aug 2010 14:34:58 +0000 (+0000)
Subject: cdefs.h: Allow __CONCAT() macro to be nested
X-Git-Tag: v3.1.8~33
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch06.html?a=commitdiff_plain;h=36fb30dfef8d99f00ab48e1c3efdede0b8ab413a;p=minix.git

cdefs.h: Allow __CONCAT() macro to be nested
---

diff --git a/include/sys/cdefs.h b/include/sys/cdefs.h
index c982b3307..f030bbce1 100644
--- a/include/sys/cdefs.h
+++ b/include/sys/cdefs.h
@@ -78,9 +78,11 @@
 /*
  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
- * The __CONCAT macro is a bit tricky -- make sure you don't put spaces
- * in between its arguments.  __CONCAT can also concatenate double-quoted
- * strings produced by the __STRING macro, but this only works with ANSI C.
+ * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
+ * mode -- there must be no spaces between its arguments, and for nested
+ * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
+ * concatenate double-quoted strings produced by the __STRING macro, but
+ * this only works with ANSI C.
  */
 
 #define	___STRING(x)	__STRING(x)
@@ -88,7 +90,8 @@
 
 #if __STDC__ || defined(__cplusplus)
 #define	__P(protos)	protos		/* full-blown ANSI C */
-#define	__CONCAT(x,y)	x ## y
+#define	__CONCAT1(x,y)	x ## y
+#define	__CONCAT(x,y)	__CONCAT1(x,y)
 #define	__STRING(x)	#x
 
 #define	__const		const		/* define reserved names to standard */