Fix build for modern C++17 and Clang 17 #28
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Modernize the project to build with contemporary toolchains: - Upgrade C++ standard from C++11 to C++17 - Update CMake minimum version to 3.16 - Fix logger comparator const-correctness for modern libc++ - Resolve namespace/class name ambiguity using inline variables - Use typedef alias to disambiguate out-of-line member definitions The dotenv class name matches its namespace, which causes parsing issues in modern C++. Fixed by using C++17 inline variables for static members and a typedef alias in the implementation.
Add a new CMake option BUILD_BOTH_LIBRARIES that allows building both static and shared libraries in a single build directory. This provides an alternative to the existing approach of building in separate directories with BUILD_SHARED_LIBS=ON/OFF, while maintaining backward compatibility with existing build scripts. Usage: cmake .. -DBUILD_BOTH_LIBRARIES=ON Produces: - libcpp_dotenv_static.a - libcpp_dotenv_shared.so (or .dylib on macOS)
- Add validation to prevent BUILD_BOTH_LIBRARIES and BUILD_SHARED_LIBS from being used together (with warning message) - Improve documentation for the cpp_dotenv alias, explaining that it points to cpp_dotenv_static when BUILD_BOTH_LIBRARIES is ON
- Add OUTPUT_NAME property so libraries are named correctly: * libcpp_dotenv.a (static) instead of libcpp_dotenv_static.a * libcpp_dotenv.so/.dylib (shared) instead of libcpp_dotenv_shared.so - Enable CMAKE_POSITION_INDEPENDENT_CODE when building shared libraries to ensure static dependencies are compiled with -fPIC - Document BUILD_BOTH_LIBRARIES option in README.md with usage examples The OUTPUT_NAME property sets only the base name; CMake automatically adds the correct platform-specific extension (.so on Linux, .dylib on macOS).
- Fix README CMake version mismatch: update from >=3.10 to >=3.16 to match CMakeLists.txt requirement - Fix Windows MSVC import library conflict: when BUILD_BOTH_LIBRARIES is ON, both static and shared libraries would produce cpp_dotenv.lib on Windows. Add IMPORT_SUFFIX "_shared.lib" to the shared library's import library to avoid this conflict on Windows/MSVC.
Add BUILD_BOTH_LIBRARIES option for TAP tests
dotenv.h: - Clarify inline variable syntax with explanatory comment - Add comment explaining why _instance cannot be inline inside class dotenv.cpp: - Rename Dotenv_Type to DotenvClass for better C++ conventions - Fix operator[] to use typedef alias consistently (avoid parsing issues) - Improve comment clarity for the global env variable definition CMakeLists.txt: - Add MSVC support for compiler flags (/W4 /Od /O2) - Improve Windows library naming: use distinct OUTPUT_NAME on MSVC to avoid conflicts between static and shared library .lib files common/libs/antlr4-cpp-runtime/CMakeLists.txt: - Update cmake_minimum_required from 3.10 to 3.16 for consistency
Address remaining Copilot feedback: env_filename is kept for backward compatibility as external code may reference dotenv::dotenv::env_filename directly. Add explanatory comment to document this.
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Summary
This PR modernizes the cpp-dotenv project to build with contemporary C++ toolchains (C++17, Clang 17+, modern CMake).
Changes
logger::position::less::operator()for modern libc++ compatibilitydotenv) using C++17 inline variablesTechnical Details
The
dotenvclass name matches its namespace, which causes C++ parser ambiguity when defining out-of-line members. This is fixed by:inlinevariables for static member definitionsTest Plan
libcpp_dotenv.abuilds without errors