1# $NetBSD: varmod-shell.mk,v 1.5 2020/11/17 20:11:02 rillig Exp $ 2# 3# Tests for the :sh variable modifier, which runs the shell command 4# given by the variable value and returns its output. 5# 6# This modifier has been added on 2000-04-29. 7# 8# See also: 9# ApplyModifier_ShellCommand 10 11# TODO: Implementation 12 13# The command to be run is enclosed between exclamation marks. 14# The previous value of the expression is irrelevant for this modifier. 15# The :!cmd! modifier turns an undefined expression into a defined one. 16.if ${:!echo word!} != "word" 17. error 18.endif 19 20# If the command exits with non-zero, an error message is printed. 21# XXX: Processing continues as usual though. 22# 23# Between 2000-04-29 and 2020-11-17, the error message mentioned the previous 24# value of the expression (which is usually an empty string) instead of the 25# command that was executed. It's strange that such a simple bug could 26# survive such a long time. 27.if ${:!echo word; false!} != "word" 28. error 29.endif 30.if ${:Uprevious value:!echo word; false!} != "word" 31. error 32.endif 33 34all: 35 @:; 36