Why does compiling my project to dll give error codes C2664 and E0289 error when compiling?

Question

BOOL CALLBACK callback(HWND hwnd, LPARAM param) {
    DWORD pid;
    GetWindowThreadProcessId(hwnd, &pid);
    if (pid == param) {
        TCHAR classNameBuf[MAX_PATH];
        GetClassName(hwnd, classNameBuf, MAX_PATH);
        std::string className(&classNameBuf[0]);
        if (className != ("MSCTFIME UI") && className != ("IME") && className != ("ConsoleWindowClass")) {
            window_handle = hwnd;
            return false;
        }
    }
    return true;
}

When I try to compile my project and run it, it gives these errors.:

Error E0289 no instance of constructor "std::basic_string<_Elem, _Traits, _Alloc>::basic_string [with _Elem=char, _Traits=std::char_traits<char>, _Alloc=std::allocator<char>]" matches the argument list

And this one

Error C2664 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>::basic_string(std::initializer_list<_Elem>,const _Alloc &)': cannot convert argument 1 from 'TCHAR *' to 'std::initializer_list<_Elem>'

Can someone point out what I am doing wrong?

Answer 1

You are calling the TCHAR-based GetClassName() macro, and you have your project set to define UNICODE, thus TCHAR is mapped to wchar_t, not char. You can't create a std::string from a wchar[] array (well, not the way you are trying to, anyway).

So, either:

• change your project settings to use the MBCS charset instead of UNICODE, so that TCHAR maps to char, and GetClassName maps to GetClassNameA().

• don't use TCHAR at all, use GetClassNameA() directly, eg:

  CHAR classNameBuf[MAX_PATH];
  GetClassNameA(hwnd, classNameBuf, MAX_PATH);
  std::string className(classNameBuf);
  if (className != "MSCTFIME UI" && ...)
  

• if you really want to use TCHAR (which you shouldn't - this is not the '90s), you can use std::basic_string<TCHAR> instead, just be sure to wrap your string literals with the TEXT() macro, eg:

  TCHAR classNameBuf[MAX_PATH] = {};
  GetClassName(hwnd, classNameBuf, MAX_PATH);
  std::basic_string<TCHAR> className(classNameBuf);
  if (className != TEXT("MSCTFIME UI") && ...)
  

• you can just avoid std::(basic_)string altogether and use lstrcmp() instead to match the same TCHAR encoding that GetClassName() uses, eg:

  TCHAR classNameBuf[MAX_PATH] = {};
  GetClassName(hwnd, classNameBuf, MAX_PATH);
  if (lstrcmp(classNameBuf, TEXT("MSCTFIME UI")) != 0 && ...)