MSVC build errors > LNK2038

LNK2038: mismatch detected

error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MT_StaticRelease' doesn't match value 'MD_DynamicRelease' in main.obj

Every object file records the C runtime and the iterator debug level it was compiled with. The linker refuses to mix object files and libraries that disagree, because they would use incompatible versions of the standard library.

Causes and fixes

1. Projects use different runtime libraries. Set the same C/C++ > Code Generation > Runtime Library in every project of the program: /MD everywhere, or /MT everywhere, with /MDd or /MTd in Debug.
2. A Release library is linked into a Debug build. A mismatch on _ITERATOR_DEBUG_LEVEL (0 against 2) means that Debug and Release code are mixed: link the Debug version of the library in Debug builds.
3. A single file overrides the project. A .cpp file can have its own Runtime Library setting. Remove the override in its properties so it inherits the project's.
4. A prebuilt third-party library uses another runtime. Use the variant built for your runtime, or rebuild it with your settings, for example with the matching vcpkg triplet.

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Related errors: LNK2019, LNK2001. See all guides.