The EM_GETSELTEXT message retrieves the currently selected text in a rich edit control.
EM_GETSELTEXT
wParam = 0;
lParam = (LPARAM) (LPSTR) lpBuf;
Parameters
lpBuf
Pointer to a buffer that receives the selected text. The calling application must ensure that the buffer is large enough to hold the selected text.
Return Values
Returns the number of characters copied, not including the terminating null character.