* Checking program called by winshow
cap prog drop wsauto
program define wsauto
	version 5.0
	local varlist "req exist"
	* Get the modified variable names into locals 1, 2 etc...
	parse "`*'"
	parse "`varlist'", parse(" ")
	while "`1'" != "" {
		* Only do check if mpg or displ has been modified:
		if "`1'" == "mpg" | "`1'" == "displ" {
			* Get index of mpg:
			local n1 : char mpg[no]
 			* Get index of displ:
			local n2 : char displ[no]
			if ${GWSvv`n1'} / ${GWSvv`n2'} > 0.5 {
				* (mpg/displ) > 0.5
				#delimit ;
				cap window stopbox rusure "The fuel efficiency per cu inch is above 0.5 which is unusual."
				"Are you sure mpg and displ are correct?"
				"Press OK to continue anyway.";
				#delimit cr
				if _rc {			/* User pressed cancel */
					exit 1
				}
				else {				/* User pressed OK */
					exit
				}
			}
			else {
				* (mpg/displ) < 0.5
				exit
			}
		}
		mac shift
	}
end