--- OpenCL/OpenCL.pm	2012/05/05 02:45:38	1.76
+++ OpenCL/OpenCL.pm	2012/05/05 12:54:03	1.77
@@ -99,6 +99,37 @@
 
 Enqueue buffer reads for your output buffer to read results.
 
+=head1 OPENCL 1.1 VS. OPENCL 1.2
+
+This module supports both OpenCL version 1.1 and 1.2, although the OpenCL
+1.2 interface hasn't been tested much for lack of availability of an
+actual implementation.
+
+Every function or method in this manual page that interfaces to a
+particular OpenCL function has a link to the its C manual page.
+
+If the link contains a F<1.1>, then this function is an OpenCL 1.1
+function. Most but not all also exist in OpenCL 1.2, and this module
+tries to emulate the missing ones for you, when told to do so at
+compiletime. You cna check whether a function was removed in OpenCL 1.2 by
+replacing the F<1.1> component in the URL by F<1.2>.
+
+If the link contains a F<1.2>, then this is a OpenCL 1.2-only
+function. Even if the module was compiled with OpenCL 1.2 header files
+and has an 1.2 OpenCL library, calling such a function on a platform that
+doesn't implement 1.2 causes undefined behaviour, usually a crash (But
+this is not guaranteed).
+
+You can find out whether this module was compiled to prefer 1.1
+functionality by ooking at C<OpenCL::PREFER_1_1> - if it is true, then
+1.1 functions generally are implemented using 1.1 OpenCL functions. If it
+is false, then 1.1 functions missing from 1.2 are emulated by calling 1.2
+fucntions.
+
+This is a somewhat sorry state of affairs, but the Khronos group choose to
+make every release of OpenCL source and binary incompatible with previous
+releases.
+
 =head1 EXAMPLES
 
 =head2 Enumerate all devices and get contexts for them.