{* *! version 1.0.2  15mar2007}{...}
    {cmd:sign(}{it:x}{cmd:)}
{p2colset 8 22 26 2}{...}
{p2col: Domain:}-8e+307 to 8e+307 and {it:missing}{p_end}
{p2col: Range:}-1, 0, 1 and {it:missing}{p_end}
{p2col: Description:}returns the sign of {it:x}: -1 if {it:x} < 0,
        0 if {it:x} = 0, 1 if {it:x} > 0, and {it:missing}
	if {it:x} is missing.{p_end}
{p2colreset}{...}
