windows: fix LNK4006 duplicate symbol warning in static CMake builds#809
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Replace `#ifndef hidapi_winapi_EXPORTS` guard in windows/hid.c with `#ifndef HIDAPI_CMAKE_V0_BUILD`, and define HIDAPI_CMAKE_V0_BUILD as a PRIVATE compile definition on the hidapi_winapi CMake target. When building with CMake, hidapi_descriptor_reconstruct.c is compiled as a separate translation unit. The old guard relied on hidapi_winapi_EXPORTS which is only set for shared (DLL) builds, causing the file to be compiled twice in static builds and producing a benign-but-noisy LNK4006 warning. The new HIDAPI_CMAKE_V0_BUILD define is set for all CMake builds (both shared and static), so hid.c never #includes the .c file when using CMake. Legacy build systems that don't define HIDAPI_CMAKE_V0_BUILD continue to work as before because hid.c still #includes the file in that case. Agent-Logs-Url: https://github.com/libusb/hidapi/sessions/a624aff3-07ad-401b-8587-87bc5203841b Co-authored-by: Youw <5939659+Youw@users.noreply.github.com>
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[WIP] Fix warnings when building hidapitester using CMake
windows: fix LNK4006 duplicate symbol warning in static CMake builds
May 19, 2026
Youw
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May 19, 2026
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When building hidapi as a static library via CMake (e.g. from hidapitester), MSVC emits a linker warning because
hidapi_descriptor_reconstruct.cis compiled twice: once as a separate CMake source and once via#includeinsidehid.c.The old guard
#ifndef hidapi_winapi_EXPORTSwas intended to prevent the double-include, buthidapi_winapi_EXPORTSis only set by MSVC for shared (DLL) builds — leaving static builds unprotected.Changes
windows/hid.c: Replace thehidapi_winapi_EXPORTSguard withHIDAPI_CMAKE_V0_BUILD:windows/CMakeLists.txt: DefineHIDAPI_CMAKE_V0_BUILDas aPRIVATEcompile definition onhidapi_winapifor all CMake builds (shared and static alike), sohid.calways skips the#includewhen building via CMake.Legacy (non-CMake) build systems remain unaffected: without the definition,
hid.ccontinues to#includethe file as before.