Thread affinity and static linking support

What's New

• Optional CPU affinity for OTel SDK threads. A new cpu_id field in the per-component YAML pins SDK-managed threads to a specific CPU core via pthread_setaffinity_np(). Defaults to -1 (no affinity), so existing configurations are unchanged. Guarded by HAVE_SCHED_H.
• Static-library builds. The wrapper itself can now be built as a .a archive (cmake -DBUILD_STATIC=ON / autotools --enable-static --disable-shared). A matching lib-type=static argument to scripts/build-bundle.sh builds the bundled opentelemetry-cpp SDK as static archives, with full transitive-dependency probing.

Bug fix

• Fixed a double free in make_shared_nothrow when the underlying allocation throws std::bad_alloc.

Build and packaging

• Bundled monorepo assembly script for opentelemetry-cpp 1.26.0.
• Auto-detected ryml lib vs lib64 via a new AX_FIND_LIBDIR macro.
• Silenced GCC 15 alloc-size, clang nullability (absl), and unused-but-set warnings under -Werror.
• Replaced GCC typeof with decltype / __typeof__ for portability.

ABI

The library libtool version was bumped from 1:1:1 to 2:0:2. The change is purely additive: it introduces a new option without altering the existing surface, so consumers continue to link against libopentelemetry_c_wrapper without modification.

Full changelog

v1.0.2...v1.1.0

Exporter thread stability and expanded YAML reference

What's New

• Pre-spawned background threads on OTLP HTTP, OTLP gRPC, OTLP File, and Elasticsearch exporters at construction time, so threads are ready before the first batch export.
• Added the background_thread_wait_for YAML option for OTLP/HTTP exporters, controlling how long the curl background thread lingers after its last request. A value of 0 (the default) keeps the thread alive indefinitely, preventing std::terminate() crashes caused by thread respawn failures inside the SDK's noexcept MaybeSpawnBackgroundThread() call.
• Split the single OTel SDK patch into numbered per-feature patches and added a dedicated patch for SetBackgroundWaitFor() support.
• No public API or ABI changes since 1.0.1.

Documentation

• Expanded the YAML configuration reference (README section 6) with detailed documentation of every configurable key for all exporter types, samplers, processors, readers, providers, signal binding, and environment variables.
• Noted manual patch and CMake option requirements for builds that do not use the provided scripts.

Build system hardening and documentation updates

What's New

• Enforced minimum OpenTelemetry C++ SDK version (>= 1.26.0) and ABI version 2 at configure time in both autotools and CMake build systems.
• Required autoconf-archive as a build dependency with a clear error message when missing.
• Made the bootstrap script abort on aclocal failure.
• Commented out aws-lc and curl build steps in build-bundle.sh; users can re-enable them as needed.

Documentation

• Added build script usage recommendations to README and README.md.
• Documented default dependency configuration and SSL/curl requirements.
• Updated AWS-LC paragraph to reflect current defaults.

opentelemetry-c-wrapper 1.0.0

opentelemetry-c-wrapper 1.0.0

First public release of the OpenTelemetry C wrapper library -- a pure C API on top of the OpenTelemetry C++ SDK,
developed by HAProxy Technologies.

Signals

All three OpenTelemetry signals are supported:

• Traces -- span creation and lifecycle, context propagation, baggage, sampling (including ParentBased per-state delegates), events, links, and exception recording.
• Metrics -- synchronous and observable instruments (counters, histograms, gauges, up-down counters), views, and multiple metric reader/exporter pairs.
• Logs -- structured log records with severity filtering and span correlation.

Exporters

Exporter	Traces	Metrics	Logs
OTLP/gRPC	yes	yes	yes
OTLP/HTTP	yes	yes	yes
OTLP/File	yes	yes	yes
OStream	yes	yes	yes
In-Memory	yes	yes	--
Zipkin	yes	--	--
Elasticsearch	--	--	yes

Highlights

• YAML-based configuration for all SDK components (exporters, processors, samplers, providers) via rapidyaml or libfyaml.
• Thread-safe data-plane operations with a 64-shard span map for low contention under concurrent workloads.
• Operations vtable design -- each signal instance carries an ops pointer, keeping the C API clean and extensible.
• Multiple processors and exporters per signal provider.
• Dropped span/log counting via delegating processors.
• SDK internal log handler exposed through the C API.
• Build support via both Autotools and CMake.
• Bundled dependency build scripts for all required libraries.
• Test suite covering tracer, meter, logger, and YAML parsing, with Docker Compose integration tests (Elasticsearch/Kibana, OTel Collector).

Tested Platforms (amd64)

Debian 11/12/13, Ubuntu 20.04/22.04/24.04, Tuxedo 24.04, RHEL 8.10/9.5/10.0, Rocky 9.5, openSUSE Leap 15.5/15.6.

License

Apache License 2.0