EM_GETFIRSTVISIBLELINE
wParam = 0; /* not used, must be zero */
lParam = 0L; /* not used, must be zero */
An application sends an EM_GETFIRSTVISIBLELINE message to determine the topmost visible line in an edit control.
This message has no parameters.
The return value is the zero-based index of the topmost visible line. For single-line edit controls, the return value is zero.
This example gets the index of the topmost visible line in an edit control:
int FirstVis;
FirstVis = (int) SendDlgItemMessage(hdlg, IDD_EDIT,
EM_GETFIRSTVISIBLELINE, 0, 0L);