1# $NetBSD: varmod-shell.mk,v 1.7 2022/01/10 20:32:29 rillig Exp $ 2# 3# Tests for the ':!cmd!' variable modifier, which runs the shell command 4# given by the variable modifier and returns its output. 5# 6# This modifier has been added on 2000-04-29. 7# 8# See also: 9# ApplyModifier_ShellCommand 10 11# The command to be run is enclosed between exclamation marks. 12# The previous value of the expression is irrelevant for this modifier. 13# The :!cmd! modifier turns an undefined expression into a defined one. 14.if ${:!echo word!} != "word" 15. error 16.endif 17 18# If the command exits with non-zero, an error message is printed. 19# XXX: Processing continues as usual though. 20# 21# Between 2000-04-29 and 2020-11-17, the error message mentioned the previous 22# value of the expression (which is usually an empty string) instead of the 23# command that was executed. 24.if ${:!echo word; false!} != "word" 25. error 26.endif 27.if ${:Uprevious value:!echo word; false!} != "word" 28. error 29.endif 30 31 32.MAKEFLAGS: -dv # to see the actual command 33_:= ${:!echo word; ${:Ufalse}!} 34.MAKEFLAGS: -d0 35 36all: 37