2007-10-20 Martin Sebor <sebor@roguewave.com>
Merged 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.
git-svn-id: https://svn.apache.org/repos/asf/incubator/stdcxx/branches/4.2.0@586797 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/include/rw/_config.h b/include/rw/_config.h
index 1872e5f..77a6145 100644
--- a/include/rw/_config.h
+++ b/include/rw/_config.h
@@ -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 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 *
