An application sends an EM_GETLINE message to copy a line of text from an edit control and place it in a specified buffer.
EM_GETLINE 
wParam = (WPARAM) line;          // line number to retrieve 
lParam = (LPARAM) (LPCSTR) lpch; // address of buffer for line 
 The return value is the number of characters copied. The return value is zero if the line number specified by the line parameter is greater than the number of lines in the edit control.
The copied line does not contain a terminating null character.
  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winuser.h.
Edit Controls Overview, Edit Control Messages, EM_LINELENGTH, WM_GETTEXT