1# $NetBSD: cond-token-var.mk,v 1.3 2020/08/20 19:43:42 rillig Exp $ 2# 3# Tests for variables in .if conditions. 4 5DEF= defined 6 7# A defined variable may appear on either side of the comparison. 8.if ${DEF} == ${DEF} 9.info ok 10.else 11.error 12.endif 13 14# A variable that appears on the left-hand side must be defined. 15.if ${UNDEF} == ${DEF} 16.error 17.endif 18 19# A variable that appears on the right-hand side must be defined. 20.if ${DEF} == ${UNDEF} 21.error 22.endif 23 24# A defined variable may appear as an expression of its own. 25.if ${DEF} 26.endif 27 28# An undefined variable generates a warning. 29.if ${UNDEF} 30.endif 31 32# The :U modifier turns an undefined variable into an ordinary expression. 33.if ${UNDEF:U} 34.endif 35