Retrieves the selected ANSI text. You can send this message explicitly or by using the Editor_GetSelTextA inline function.
wParam = (WPARAM) (UINT) nBufferSize;
lParam = (LPARAM) (LPSTR) szBuffer;
Specifies the maximum number of characters in bytes to copy to the buffer, including the NULL character.
Pointer to the buffer that will receive the text.
If nBufferSize. is zero, the return value is the required size, in bytes, for a buffer that can receive the text. If nBufferSize. is not zero, the return value is not used.