Error in declarator or parameters

[StrikerRUS]

Now that sphinx-doc/sphinx#7423 is merged and Sphinx 3.0.1 is released, we can say that breathe 4.15.0 has a regression problem with some function definitions which worked well before.

Repro can be taken from my comment in Sphinx repo: sphinx-doc/sphinx#7423 (comment).

The problem is in the following functions.

LIGHTGBM_C_EXPORT int LGBM_BoosterFree(int handle);

Warning, treated as error:
/home/travis/build/microsoft/LightGBM/docs/C-API.rst:4:Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name, got keyword: int [error at 21]
  LIGHTGBM_C_EXPORT int LGBM_BoosterAddValidData(BoosterHandle handle, const  DatasetHandle valid_data)
  ---------------------^
Makefile:20: recipe for target 'html' failed

Or is it a bug at Sphinx side?

[jakobandersen]

This is something that should be enhanced on the Sphinx side. The problem is that it is not a valid function declaration, though I guess LIGHTGBM_C_EXPORT expands to an an attribute for symbol visibility? I have opened an issue to track the feature.

[StrikerRUS]

@jakobandersen Thank you very much for that prompt response!

Here is the LIGHTGBM_C_EXPORT definition: https://github.com/microsoft/LightGBM/blob/master/include/LightGBM/export.h

[jakobandersen]

This should be fixed in Sphinx 3.0.2 once it is released (you can try with the 3.0.x branch). You will need to put

c_id_attributes = ['LIGHTGBM_C_EXPORT']

in conf.py to tell the parser to recognize the custom attribute.

[StrikerRUS]

Thanks a lot for the prompt fix! I'll try it on RTD site right after the 3.0.2 release.

[StrikerRUS]

@jakobandersen Everything works fine with Sphinx 3.0.2! Thank you very much for the awesome support!