MSVC build errors > C2664

C2664: cannot convert argument

error C2664: 'int MessageBoxW(HWND,LPCWSTR,LPCWSTR,UINT)': cannot convert argument 2 from 'const char [6]' to 'LPCWSTR'

An argument of a function call cannot be converted to the type of its parameter.

Causes and fixes

1. A narrow string is passed to a Unicode Windows function. With Character Set set to Unicode, MessageBox is MessageBoxW and expects wide strings: write L"Hello", call MessageBoxA, or use TEXT("Hello").
2. A temporary is passed to a non-const reference. A parameter std::string& does not accept a literal or a temporary: take const std::string& when the function does not change it.
3. A const object is passed to a non-const parameter. Make the parameter const, or pass a copy.
4. The arguments are in the wrong order. Compare the call with the declaration the message shows; another overload may be the one you meant.

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Related errors: C2440. See all guides.