What is the issue you have?

Linker error LNK2005:

unit-regression2.obj : error LNK2005: "public: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > * sax_no_exception::error_string" (?error_string@sax_no_exception@@2PEAV?$basic_string@DU?$char_traits@D@std@@V?$allo
cator@D@2@@std@@EA) already defined in unit-disabled_exceptions.obj [build\json\test\json_unit.vcxproj]
build\json\test\Release\json_unit.exe : fatal error LNK1169: one or more multiply defined symbols found [build\json\test\json_unit.vcxproj]

Can you provide a small but working solution / fix?

Add a namespace in both files json\test\src\unit-disabled_exceptions.cpp and json\test\src\unit-regression2.cpp:

namespace
{
  class sax_no_exception : public nlohmann::detail::json_sax_dom_parser<json>
  {
  ...
  };
  std::string* sax_no_exception::error_string = nullptr;
}  // namespace

What is the expected behavior?

No link error

And what is the actual behavior instead?

LNK2005 error

Which compiler and operating system are you using?

• Compiler: Visual Studio 2019 16.11.1 Professional
• Operating system: Windows 10 21H1

Which version of the library did you use?

• latest release version 3.10.0 (zip file)
• other release - please state the version: ___
• the develop branch

If you experience a compilation error: can you compile and run the unit tests?

• yes
• no - please copy/paste the error message below