= OpenCL-Registry

The OpenCL-Registry repository contains the OpenCL API and Extension
Registry, including specifications, reference pages and reference cards, and
the enumerant registry. It is also used as a backing store for the web view
of the registry at https://www.khronos.org/registry/cl/ ; commits to the
master branch of this repository will be reflected there.

In the past, the OpenCL registry was maintained in a public Subversion
repository. The history in that repository has not been imported to github,
but it is still available at
https://cvs.khronos.org/svn/repos/registry/trunk/public/cl/ .

== Reserving OpenCL Enumerant Ranges

OpenCL enumerants are documented in 'xml/cl.xml'. New ranges can be allocated
by proposing a pull request to master modifying this file, following the
existing examples. Allocate ranges starting at the lowest free values
available (search for "Reserved for vendor extensions"). Ranges are not
officially allocated until your pull request is *accepted* into master. At
that point you can use values from your assigned range for API extensions.

== Adding Extension Specifications

Extension specification documents can be added by proposing a pull request
to master, adding the specification '.txt' file under
'extensions/<vendor>/filename.txt'. You must also:

* Modify 'extensions/registry.py' to include the extension, using the next
  free extension number. Execute the python script 'nextfree.py' in the
  'extensions/' directory to find the next free number. The extension `flags`
  must be marked as `public` , similar to other entries in 'registry.py',
  for the extension to be linked from the registry index page.
* Include that extension number in the extension specification document
* In the 'extensions/' directory, `make` to regenerate the HTML index file
  'clext.php' from 'registry.py'. If this doesn't succeed due to not having
  the right Python version or something like that, we'll take care of it
  when merging to master.
* We are no longer registering extension numbers in 'xml/cl.xml', for
  consistency with the combined GL registry scripts.

Sometimes extension text files contain inappropriate UTF-8 characters. They
should be restricted to the ASCII subset of UTF-8 at present. They can be
removed using the iconv Linux command-line tool via

    iconv -c -f utf-8 -t ascii filename.txt

(see internal Bugzilla issue 16141 for more).

We will be transitioning to an asciidoc-based extension specification format
at some point.

== Repository Contents

Interesting files in this repository include:

* 'index.php' - toplevel index page for the web view. This relies on PHP
  include files found elsewhere on https://www.khronos.org and so is not very useful
  in isolation.
* 'xml/cl.xml' - enumerant and extension number registry. Documents the
  assigned OpenCL enumerant ranges, and the names and index numbers assigned
  to OpenCL extension specifications.
* 'extensions/' - OpenCL extension specifications, grouped into
  vendor-specific subdirectories.
** 'extensions/registry.py' - extension registry.
** 'extensions/makeindex.py' - create HTML extension indices from 'registry.py'.
** 'extensions/nextfree.py' - determine the next free extension number in
   'registry.py'.
* 'sdk/' - OpenCL reference pages and reference cards. There are separate sets
  for each API version.
* 'specs/' - OpenCL specification documents.