Cannot be built externally with Asterisk 16

[bernhardschmidt]

Building an external shared module (with the Makefile opposed to patching the Asterisk source) does not work anymore with Asterisk 16. It probably doesn't work starting with Asterisk 14, as this is apparently the version where the very very lightly documented requirement for AST_MODULE_SELF_SYM has been introduced.

https://issues.asterisk.org/jira/browse/ASTERISK-26278
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=919828

gcc -o codecs/codec_opus_open_source.so  -DAST_MODULE=\"codec_opus_open_source\" -Wdate-time -D_FORTIFY_SOURCE=2 -g -O2 -fdebug-prefix-map=/<<BUILDDIR>>/asterisk-opus-13.7+20171009=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -g3 -O3 -lopus -shared -Wl,-z,relro codecs/codec_opus_open_source.c
In file included from codecs/codec_opus_open_source.c:39:
/usr/include/asterisk.h:232:2: error: #error "Externally compiled modules must declare AST_MODULE_SELF_SYM."
 #error "Externally compiled modules must declare AST_MODULE_SELF_SYM."
  ^~~~~
In file included from codecs/codec_opus_open_source.c:56:
codecs/codec_opus_open_source.c: In function 'load_module':
codecs/codec_opus_open_source.c:833:8: error: 'AST_MODULE_SELF' undeclared (first use in this function); did you mean 'AST_MODULE_INFO'?
  res = ast_register_translator(&opustolin);
        ^~~~~~~~~~~~~~~~~~~~~~~
codecs/codec_opus_open_source.c:833:8: note: each undeclared identifier is reported only once for each function it appears in
make[1]: *** [Makefile:50: codecs/codec_opus_open_source.so] Error 1
make[1]: Leaving directory '/<<BUILDDIR>>/asterisk-opus-13.7+20171009'

[bernhardschmidt]

Note that other projects building external modules have resolved this by setting -DAST_MODULE_SELF_SYM to something like __internal_<modulename>_self, i.e. zaf/Asterisk-Flite@2bdc757 . This seems to work for asterisk-opus as well (at least it builds), but I have no idea what it does.

[traud]

Puh, I never tested that code with Asterisk 14 or newer. Thanks for the note!

Yes, that is the solution. The same was done in Asterisk itself (see the modules pbx_ael and codec_lpc10). Are you able to create a Pull Request? That way, it is easier for me to merge that change (as you have tested it already) and you get a linked contributor.

And yes, after a bit of Git blame investigation, the original change happened back in May 2015 with Asterisk 14 already:

• Issue report: ASTERISK-25056
• Code review: Gerrit-355
• Code commit: asterisk/asterisk@a8bfa9e

It was code clean-up, adding an additional burden on external modules. If you do not know how to create a Pull Request, you can use the edit interface of the GitHub webpage instead. That creates a Pull Request automatically. If all this is too complicated, just say so, and I change it directly.