openmp_wrapper.h stubs signature use __GOMP_NOTHROW

[bsergean]

Fix #3915. OpenMP stubs do not use the noexcept attibute which is present in the gcc version of openmp, and which trigger compilation errors as seen below. dmlc-core uses the same technique and macro.

/usr/lib/gcc/x86_64-linux-gnu/9/include/omp.h:114:12: error: declaration of ‘int omp_get_thread_num() noexcept’ has a different exception specifier
114 | extern int omp_get_thread_num (void) __GOMP_NOTHROW;
| ^~~~~~~~~~~~~~~~~~
...
xxx/include/LightGBM/utils/openmp_wrapper.h:81:14: note: from previous declaration ‘int omp_get_thread_num()’
81 | inline int omp_get_thread_num() {return 0;}
| ^~~~~~~~~~~~~~~~~~

[bsergean]

The lint plan fails with cpplint not being found. Sounds like a setup issue, and that is ran on travis it seems. All the other checks look happy though.

[StrikerRUS]

cpplint is working now and yields the following errror:

include/LightGBM/utils/openmp_wrapper.h:96:  Using C-style cast.  Use static_cast<int>(...) instead  [readability/casting] [4]

@bsergean Could you please fix it?

[bsergean]

include/LightGBM/utils/openmp_wrapper.h:96:  Using C-style cast.  Use static_cast<int>(...) instead  [readability/casting] [4]

On line 96 there isn't any cast that I can see.

Do you know what's going on ? Is it in the inlined code that a cast exists ?

[StrikerRUS]

@bsergean

Do you know what's going on ?

Sorry, I'm not a cpp coder. If you are sure this error is false positive, feel free to mark that line as // NOLINT or // NOLINTNEXTLINE.

[StrikerRUS]

To cpp reviewers.
As we do not test threadless version of LightGBM on our CIs, I've run some tasks manually with -DUSE_OPENMP=OFF flag.
All builds with gcc 10.2.0 on macOS, gcc 4.8.4 on Linux, Clang 10.0.0 on Linux, AppleClang 9.1.0.9020039 on macOS were passed.

[guolinke]

Thank you!

[StrikerRUS]

@jameslamb Your review comment was addressed I believe, but your review blocks merging. Could you please unblock?

dismiss

[jameslamb]

sorry, didn't realize my review was blocking

[github-actions]

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