.wh

.wh 

n

 [

xx

]

The "when" request. When position n is reached, execute macro xx ; negative values are with respect to page bottom. If xx is not supplied, remove any trap(s) at that location. (A trap is the position on the page where a given macro is executed.) Two traps can be at the same location if one is moved over the other with .ch . They cannot be placed at the same location with .wh .