1# $NetBSD: var-op-append.mk,v 1.9 2021/04/04 10:13:09 rillig Exp $ 2# 3# Tests for the += variable assignment operator, which appends to a variable, 4# creating it if necessary. 5 6# Appending to an undefined variable is possible. 7# The variable is created, and no extra space is added before the value. 8VAR+= one 9.if ${VAR} != "one" 10. error 11.endif 12 13# Appending to an existing variable adds a single space and the value. 14VAR+= two 15.if ${VAR} != "one two" 16. error 17.endif 18 19# Appending an empty string nevertheless adds a single space. 20VAR+= # empty 21.if ${VAR} != "one two " 22. error 23.endif 24 25# Variable names may contain '+', and this character is also part of the 26# '+=' assignment operator. As far as possible, the '+' is interpreted as 27# part of the assignment operator. 28# 29# See Parse_Var 30C++= value 31.if ${C+} != "value" || defined(C++) 32. error 33.endif 34 35# Before var.c 1.793 from 2021-02-03, the variable name of a newly created 36# variable was expanded two times in a row, which was unexpected but 37# irrelevant in practice since variable names containing dollars lead to 38# strange side effects in several other places as well. 39.MAKEFLAGS: -dv 40VAR.${:U\$\$\$\$\$\$\$\$}+= dollars 41.MAKEFLAGS: -d0 42.if ${VAR.${:U\$\$\$\$\$\$\$\$}} != "dollars" 43. error 44.endif 45 46all: 47