Author: sebor
Date: Sat Oct 20 13:52:32 2007
New Revision: 586799

URL: http://svn.apache.org/viewvc?rev=586799&view=rev
Log:
2007-10-20  Martin Sebor  <sebor@roguewave.com>

	Copied rev 586796 from branches/4.2.x.
	* _config.h (_RWSTD_VER): Corrected comments explaining source
	and binary compatibiliy rules controlling changes to the library
	version number.

Modified:
    incubator/stdcxx/trunk/include/rw/_config.h

Modified: incubator/stdcxx/trunk/include/rw/_config.h
URL: http://svn.apache.org/viewvc/incubator/stdcxx/trunk/include/rw/_config.h?rev=586799&r1=586798&r2=586799&view=diff
==============================================================================
--- incubator/stdcxx/trunk/include/rw/_config.h (original)
+++ incubator/stdcxx/trunk/include/rw/_config.h Sat Oct 20 13:52:32 2007
@@ -41,10 +41,10 @@
 //                    | | | |
 //                   MMmmuupp
 //                    | | | |
-//                    | | | +--- pp = patch release number
-//                    | | +----- uu = micro release number
-//                    | +------- mm = minor release number
-//                    +--------- MM = major release number
+//                    | | | +--- pp = patch version number
+//                    | | +----- uu = micro version number
+//                    | +------- mm = minor version number
+//                    +--------- MM = major version number
 
 // library version string (patch number included only if non-zero)
 #define _RWSTD_VER_STR   "4.2.0"
@@ -55,13 +55,22 @@
 #define _RWSTD_VER_MICRO ((_RWSTD_VER >>  8) & 0xff)
 #define _RWSTD_VER_PATCH (_RWSTD_VER & 0xff)
 
-// Two libraries are Source Compatible if they have the same major
-// release number. Libraries whose major release numbers differ may
-// or may not be source compatible.
-// Two libraries are Binary Compatible (symbol-wise and functionally)
-// if they have the same major and minor release numbers. Libraries
-// whose major and minor release numbers differ may or may not be binary
-// compatible.
+// a newer release of stdcxx is backward source and binary compatible
+// with an older release if both releases share the same major version
+// number; stdcxx releases whose major version numbers differ may or
+// may not be source or binary compatible
+
+// two releases of stdcxx are forward (as well as backward) source and
+// binary compatible if both releases share the same major and minor
+// version numbers
+
+// backward compatibility means that a program linked with an older
+// release of a library will not be adversely affected by upgrading
+// to a more recent release of the same library
+
+// forward compatibility means that a program linked with a newer
+// release of a library will not be adversely affected by downgrading
+// to an older release of the same library
 
 /**************************************************************************
  * OVERRIDES FOR CONFIGURATION MACROS                                     *