void tmargin (marginch) FNTPLT.C Level 1
float marginch Distance of top margin of text plot in inches (or cm) from the edge of a full-page output.
tmargin() must be called every time you start a new page of text plot. It determines the top position of any text on the 
page. It must be called before ctline(), ltline(), rtline(), or lcrline(). The first line of text will be placed below this by a distance height*ratio, where height is the height of the current line of text and ratio is the line spacing factor [see linesp()]. To get text as near to the top of the page as possible, you might want to call linesp(1.1) before your first line of text.