[EXPORTER] OTLP file: use thread-safe file/io

[owent]

Fixes #2674

Changes

• Use fwrite, fflush to keep it thread-safety.
• Add OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND , OPENTELEMETRY_SANITIZER_NO_MEMORY , OPENTELEMETRY_SANITIZER_NO_THREAD, OPENTELEMETRY_SANITIZER_NO_ADDRESS, OPENTELEMETRY_HAVE_BUILTIN, OPENTELEMETRY_HAVE_FEATURE, OPENTELEMETRY_HAVE_ATTRIBUTE, OPENTELEMETRY_HAVE_CPP_ATTRIBUTE

For significant contributions please make sure you have completed the following items:

• [ ] CHANGELOG.md updated for non-trivial changes
• [x] Unit tests have been added
• [ ] Changes in public API reviewed

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 87.67%. Comparing base (497eaf4) to head (93ec062). Report is 77 commits behind head on main.

Additional details and impacted files

[](https://app.codecov.io/gh/open-telemetry/opentelemetry-cpp/pull/2675?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) ```diff @@ Coverage Diff @@ ## main #2675 +/- ## ========================================== + Coverage 87.12% 87.67% +0.55% ========================================== Files 200 190 -10 Lines 6109 5851 -258 ========================================== - Hits 5322 5129 -193 + Misses 787 722 -65 ``` | [Files](https://app.codecov.io/gh/open-telemetry/opentelemetry-cpp/pull/2675?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | Coverage Δ | | |---|---|---| | [api/include/opentelemetry/nostd/string\_view.h](https://app.codecov.io/gh/open-telemetry/opentelemetry-cpp/pull/2675?src=pr&el=tree&filepath=api%2Finclude%2Fopentelemetry%2Fnostd%2Fstring_view.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-YXBpL2luY2x1ZGUvb3BlbnRlbGVtZXRyeS9ub3N0ZC9zdHJpbmdfdmlldy5o) | `97.96% <100.00%> (ø)` | | ... and [75 files with indirect coverage changes](https://app.codecov.io/gh/open-telemetry/opentelemetry-cpp/pull/2675/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry)

[owent]

• file iostream operations are not thread safe when multiple threads uses the same stream

file iostream operations are not thread safe when multiple threads uses the same stream(we got data race from std::basic_streambuf<CharT,Traits>::xsputn when using tsan). But fwrite and fflush are thread safe when multiple threads uses the same FILE handle.

You are right, fwrite(data.data(), 1, data.size(), out.get()); and fputc('\n', out.get()); still have concurrency problems here. I have move the codes to append EOL in the caller.

[marcalff]

@esigo Hi Ehsan. Any comments for the code review ?