+.br
+1,12,20,44
+.SS Margins
+A few terminals expose a means of changing their left and right margins.
+\fB@TABS@\fP supports this feature with an option.
+.TP 5
+.BI +m \ margin
+The effect depends on whether the terminal has the margin capabilities:
+.RS
+.bP
+If the terminal provides the capability for setting the left margin,
+\fB@TABS@\fP uses this,
+and adjusts the available tab stop widths.
+.bP
+If the terminal does not provide the margin capabilities,
+\fB@TABS@\fP imitates their effect,
+putting tab stops at appropriate places on each line.
+The terminal's left margin is not modified.
+.RE
+.IP
+If the
+.I margin
+parameter is omitted,
+the default is 10.
+Use
+.B +m0
+to reset the left margin,
+that is,
+to make it the left edge of the terminal's display.
+Before setting a left margin,
+\fB@TABS@\fP resets the margin to reduce problems that might arise
+from moving the cursor to the left of the current left margin.
+.PP
+When setting or resetting the left margin,
+\fB@TABS@\fP may also reset the right margin.
+.SH FILES
+.TP
+.I @DATADIR@/tabset
+tab stop initialization database