Re: Dynamic modules: MODULE_HANDLE_SIGNALS etc.

[Eli Zaretskii]

> From: Philipp Stephani <address@hidden>
> Date: Wed, 25 Nov 2015 18:50:05 +0000
> Cc: address@hidden
> 
> I left them out purely for performance reasons: these macros both call setjmp
> and possibly malloc, which can incur a significant penalty, especially for
> environment functions that are very small otherwise (e.g. eq or is_not_nil).

Be that as it may, I really don't think we have any reasonable
alternative.  Anything else will be a bug waiting to happen.

>     and
>     in fact come up with a wrapper around calls to Emacs functions and
>     macros that will catch signals and throws, and make a point of calling
>     each such function/macro through that wrapper.
> 
> My first approach was to create such a wrapper function, but I quickly 
> realized
> that it's too much of a hassle. Existing wrapper functions are e.g.
> internal_condition_case in eval.c, but you'd need one wrapper function for 
> each
> signature, which quickly results in excessive code duplication. Therefore I
> used the macros.

Maybe we could come up with some clever macro wrappers instead.
Macros are not really bound by function signature limitations, so
maybe there is a way.

Failing that, we will have to clearly document that use of these
macros in every emacs-module.c function is mandatory.  And maybe also
have only one macro instead of 2, which catches both signals and
throw's.