Add experimental C/C++ implementation for process context OTEP

process-context/README.md

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+# OpenTelemetry Process Context (Under development)
+
+This folder contains experimental implementations for the specification proposed in https://github.com/open-telemetry/opentelemetry-specification/pull/4719 .
+
+The process context OTEP introduces a standard mechanism for OpenTelemetry SDKs to publish process-level resource attributes for access by out-of-process readers such as the OpenTelemetry eBPF Profiler.

process-context/c-and-cpp/.gitignore

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+build/

process-context/c-and-cpp/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.10)
+project(otel_process_ctx C CXX)
+
+# Set C standard
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+
+# Set C++ standard for C++ variants
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Note: We build here with both a C compiler as well as a C++ compiler because this implementation is expected to be
+# used with either, and we want to make sure we build cleanly on either (so we don't accidentally add C-isms that C++
+# doesn't like, or vice-versa)
+
+# Compiler flags
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -O2 -fPIC -ggdb3")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -O2 -fPIC -ggdb3")
+
+# Source files
+set(SOURCES otel_process_ctx.c)
+set(SOURCES_CXX otel_process_ctx.cpp)
+
+# Create shared library
+add_library(otel_process_ctx SHARED ${SOURCES})
+set_target_properties(otel_process_ctx PROPERTIES
+    OUTPUT_NAME "otel_process_ctx"
+)
+
+# Create static library
+add_library(otel_process_ctx_static STATIC ${SOURCES})
+set_target_properties(otel_process_ctx_static PROPERTIES
+    OUTPUT_NAME "otel_process_ctx"
+)
+
+# Create shared noop library
+add_library(otel_process_ctx_noop SHARED ${SOURCES})
+set_target_properties(otel_process_ctx_noop PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_noop"
+)
+target_compile_definitions(otel_process_ctx_noop PRIVATE OTEL_PROCESS_CTX_NOOP=1)
+
+# Create static noop library
+add_library(otel_process_ctx_noop_static STATIC ${SOURCES})
+set_target_properties(otel_process_ctx_noop_static PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_noop"
+)
+target_compile_definitions(otel_process_ctx_noop_static PRIVATE OTEL_PROCESS_CTX_NOOP=1)
+
+# Create C++ shared library
+add_library(otel_process_ctx_cpp SHARED ${SOURCES_CXX})
+set_target_properties(otel_process_ctx_cpp PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_cpp"
+    CXX_STANDARD 11
+    CXX_STANDARD_REQUIRED ON
+)
+
+# Create C++ static library
+add_library(otel_process_ctx_cpp_static STATIC ${SOURCES_CXX})
+set_target_properties(otel_process_ctx_cpp_static PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_cpp"
+    CXX_STANDARD 11
+    CXX_STANDARD_REQUIRED ON
+)
+
+# Create C++ shared noop library
+add_library(otel_process_ctx_cpp_noop SHARED ${SOURCES_CXX})
+set_target_properties(otel_process_ctx_cpp_noop PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_cpp_noop"
+    CXX_STANDARD 11
+    CXX_STANDARD_REQUIRED ON
+)
+target_compile_definitions(otel_process_ctx_cpp_noop PRIVATE OTEL_PROCESS_CTX_NOOP=1)
+
+# Create C++ static noop library
+add_library(otel_process_ctx_cpp_noop_static STATIC ${SOURCES_CXX})
+set_target_properties(otel_process_ctx_cpp_noop_static PROPERTIES
+    OUTPUT_NAME "otel_process_ctx_cpp_noop"
+    CXX_STANDARD 11
+    CXX_STANDARD_REQUIRED ON
+)
+target_compile_definitions(otel_process_ctx_cpp_noop_static PRIVATE OTEL_PROCESS_CTX_NOOP=1)
+
+# Set include directories
+target_include_directories(otel_process_ctx PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_noop PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_noop_static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_cpp PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_cpp_static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_cpp_noop PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(otel_process_ctx_cpp_noop_static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+# Create example executable
+add_executable(example_ctx example_ctx.c)
+target_link_libraries(example_ctx otel_process_ctx)
+
+# Create example noop executable
+add_executable(example_ctx_noop example_ctx.c)
+target_link_libraries(example_ctx_noop otel_process_ctx_noop)
+
+# Install rules
+install(TARGETS otel_process_ctx otel_process_ctx_static otel_process_ctx_noop otel_process_ctx_noop_static
+                otel_process_ctx_cpp otel_process_ctx_cpp_static otel_process_ctx_cpp_noop otel_process_ctx_cpp_noop_static
+                example_ctx example_ctx_noop
+    LIBRARY DESTINATION lib
+    ARCHIVE DESTINATION lib
+    RUNTIME DESTINATION bin
+)
+install(FILES otel_process_ctx.h DESTINATION include)