Call c_str() to get a const char * (LPCSTR) from a std::string.
It’s all in the name:
LPSTR – (long) pointer to string – char *
LPCSTR – (long) pointer to constant string – const char *
LPWSTR – (long) pointer to Unicode (wide) string – wchar_t *
LPCWSTR – (long) pointer to constant Unicode (wide) string – const wchar_t *
LPTSTR – (long) pointer to TCHAR (Unicode if UNICODE is defined, ANSI if not) string – TCHAR *
LPCTSTR – (long) pointer to constant TCHAR string – const TCHAR *
You can ignore the L (long) part of the names — it’s a holdover from 16-bit Windows.