> \Z'\l'4i''four inch If you need a text line of a specified width, you can switch the rule and the label around:
.de LR \Z'\\$1 inch'\D'l \\$1i 0' .. Using this .LR 1 .LR 2 .LR 3 .LR 4 .LR 5 .LR 6 will then indeed trigger the length warning for the above lines 5 & 6.
