Re: emacs-module is not GPL compatible (Windows)

[Óscar Fuentes]

Mambo Levis <mambo.levis@gmail.com> writes:

First of all, please don't send usage questions to bug-gnu-emacs. That
list is for reporting defects, suggesting enhancements and submitting
patches.

> I build the emacs-sqlite3 project in Windows using MINGW
> (mingw64_shell.bat) and the following message appears whenI requiere
> the module: sqlite3-core.dll is not GPL compatible
>
> Questions: 
> 1. Have anybody tried to build this project in windows using MINGW or
> Visual Studio?

Which project?

> 2. Do you have any idea about the error message: sqlite3-core.dll is
> not GPL compatible?

Most likely the module does not define and export the symbol
plugin_is_GPL_compatible, as described here:

http://diobla.info/blog-archive/modules-tut.html#sec-2-2

> I found this project (sqlite3-core) more interesting/valuable for
> testing the new emacs-module than the default provided (mod-test) in
> emacs-25.1-src/modules
> Repository: https://github.com/syohex/emacs-sqlite3

Ah, *that* project :-)

> I also found and build a similar
> project https://github.com/thom-jenks/emacs-sqlite but unfortunately
> with the same problem: it is not GPL compatible

The problem is that the code does not export the symbol
plugin_is_GPL_compatible. On GNU/Linux symbols are exported by default
when you build the shared library, but that's not the case of Windows
where you must export them explicitly.

Try changing

int plugin_is_GPL_compatible;

to

__declspec(dllimport) int plugin_is_GPL_compatible;

Probably you will also need to change

int
emacs_module_init(struct emacs_runtime *ert)

to

int __declspec(dllimport)
emacs_module_init(struct emacs_runtime *ert)

Hope this helps.