CurLine
New value of the current line index, or -1 to retain the current value.
CurPos
New value of the cursor position in the line, or -1 to retain the current value.
CurTabPos
New value of the cursor position on the screen, or -1 to keep the current value.
If the current line doesn't contain tab characters, CurTabPos has the same meaning, as CurPos.
Both CurPos and CurTabPos should not be specified, either one or the other must be set to -1.
TopScreenLine
New value of the first visible line index, or -1 to keep the current value.
LeftPos
New value of the leftmost visible position of the text on the screen, or -1 to keep the current value.
Overtype
Set to 0 for insert mode, 1 for overtype mode, -1 to keep the current mode.