Why Does Clang with libc in C 0x Mode Fail to Link Boost::Program_Options?

Why clang with libc in C 0x Mode Fails to Link Boost::Program_Options Example

The given snippet demonstrates an issue when attempting to compile and link boost::program_options with clang utilizing libc in C 0x mode.

Problem Analysis

The compilation error stems from the incompatibility between libc and libstdc , the default standard library implemented by g . libc employs different implementation details for std::string, introducing an ABI (Application Binary Interface) difference from libstdc .

Solution

To resolve this issue, it is necessary to rebuild Boost using clang with the -stdlib=libc flag. This ensures that the Boost libraries are compiled against the same standard library that the executable is being linked against. It harmonizes the ABI of std::string across the Boost libraries and the program being compiled.

Technical Explanation

libc leverages inline namespaces to alter the ABI of std::string without modifying its API. This creates a perceived discrepancy between the two libraries, where std::string from libstdc and std::__1::string from libc are treated as distinct data structures by the linker.

By rebuilding Boost with the appropriate standard library, the symbol definitions for boost::program_options match those expected by the linker, enabling successful linking.

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