RFR: Add jextract guide [v5]

Mon Apr 15 13:25:13 UTC 2024

On Mon, 15 Apr 2024 13:07:34 GMT, Nir Lisker <nlisker at openjdk.org> wrote:

>> It's defined in the C file in the snippet above.
>
> But we can't call the c function directly. Are there more java bindings that jextract generates?

Sorry, the example assumes that that the `call_me_back` function is also defined in the header file that jextract extracted, so a Java method would be generated for it.

-------------

PR Review Comment: https://git.openjdk.org/jextract/pull/231#discussion_r1565784414