Re: Dynamic module building and reloading

[Nicolas Martyanoff <nicolas@n16f.net>]

Got it, thank you for responding this quickly. 

Are there technical limitations against reloading or is this just a case of “if you need it send a patch”? I know that some platforms may have issues with it; but I use foreign library reloading in Common Lisp on Linux all the time, and it also works en BSD.

Nicolas Martyanoff
https://www.n16f.net
nicolas@n16f.net

> On 13 Jun 2023, at 18:55, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> 
>> 
>> From: Nicolas Martyanoff <nicolas@n16f.net>
>> Date: Tue, 13 Jun 2023 18:11:47 +0200
>> 
>> 1. There does not seem to be any builtin utilities to deal with
>> the process of building and loading shared library. I ended up writing a
>> couple elisp functions to find the location of the C file, spawn cc,
>> load the shared library… Is this the expected method? In this state, it
>> would seem that every Emacs packages using dynamic modules has to write
>> its own build/load code.
> 
> The expected method of building a shared library is the same as you'd
> use for building any other shared library out there.  The Emacs
> modules aren't special in any way, and the details of their build
> procedures depend on what code you are compiling in, which other
> libraries you need to link against, etc.  There's no way an Emacs
> command could cover all that.  However, if you write a Makefile to
> compile and link the module, you can use "M-x compile" to run the Make
> utility to build your module.
> 
>> 2. It seems that once a dynamic module has been loaded, it cannot be
>> reloaded after the shared library has been rebuilt. A Google search
>> seems to confirm it. Is there a workaround? If I pursue my little
>> project, I'll have to write quite a lot of C code in the dynamic module;
>> I *really* do not want to restart Emacs to test every single
>> modification.
> 
> We don't have a facility to unload a module, no.  The usual way of
> testing your development code is to start a new scratch session (in
> addition to your production Emacs session) each time you recompile a
> module.