Update README.md for docs

README.md

@@ -7,3 +7,31 @@ Inspired by [gl3w](https://github.com/skaslev/gl3w), cl3w is the easiest way to
 Its main part is a simple [cl3w_gen.py](./cl3w_gen.py) python script that downloads the Khronos [cl.xml](https://github.com/KhronosGroup/OpenCL-Docs/blob/main/xml/cl.xml) and generates cl3w.h and cl3w.c from it. Those files can then be added and linked into your project.
 
 See [vector_add.cpp](test/vector_add.cpp) for an functional example.
+
+## Example
+
+As of writing, the `cl.xml` from https://raw.githubusercontent.com/KhronosGroup/OpenCL-Docs/v3.0.10/xml/cl.xml is tested.
+
+```bash
+python ./cl3w_gen.py --cl_std=1.2 --cl_xml=https://raw.githubusercontent.com/KhronosGroup/OpenCL-Docs/v3.0.10/xml/cl.xml
+cmake -S. -Bbuild -GNinja
+cmake --build build
+./build/test/vector_add
+```
+
+If you `ldd` on *nix or `dumpbin.exe /DEPENDENTS` on Windows, OpenCL library will not show in the list. If you don't
+understand what this means, then you probably don't need cl3w.
+
+## Documentation
+
+No docs at the moment.
+
+Public interfaces::
+
+- `cl3wInit()`: Load OpenCL library from builtin library search list at runtime and initialize all OpenCL APIs.
+- `cl3wInit2(...)`: Load OpenCL library form user provided pathes and initialize all OpenCL APIs.
+- `cl3wUnload()`
+
+User facing macros:
+
+- `CL3W_NO_CL_API_DEFINES`: If not defined, OpenCL APIs names are preprocessed to be dynamically loaded function pointers. Save one round trip of function call indirection.