1*22619282SSimon J. Gerraty# $NetBSD: varmod-shell.mk,v 1.10 2024/07/05 19:47:22 rillig Exp $ 22c3632d1SSimon J. Gerraty# 3b0c40a00SSimon J. Gerraty# Tests for the ':!cmd!' variable modifier, which runs the shell command 4b0c40a00SSimon J. Gerraty# given by the variable modifier and returns its output. 5e2eeea75SSimon J. Gerraty# 6e2eeea75SSimon J. Gerraty# This modifier has been added on 2000-04-29. 7e2eeea75SSimon J. Gerraty# 8e2eeea75SSimon J. Gerraty# See also: 9e2eeea75SSimon J. Gerraty# ApplyModifier_ShellCommand 102c3632d1SSimon J. Gerraty 11e2eeea75SSimon J. Gerraty# The command to be run is enclosed between exclamation marks. 12e2eeea75SSimon J. Gerraty# The previous value of the expression is irrelevant for this modifier. 13e2eeea75SSimon J. Gerraty# The :!cmd! modifier turns an undefined expression into a defined one. 14e2eeea75SSimon J. Gerraty.if ${:!echo word!} != "word" 15e2eeea75SSimon J. Gerraty. error 16e2eeea75SSimon J. Gerraty.endif 17e2eeea75SSimon J. Gerraty 18e2eeea75SSimon J. Gerraty# If the command exits with non-zero, an error message is printed. 19e2eeea75SSimon J. Gerraty# XXX: Processing continues as usual though. 20e2eeea75SSimon J. Gerraty# 21e2eeea75SSimon J. Gerraty# Between 2000-04-29 and 2020-11-17, the error message mentioned the previous 22e2eeea75SSimon J. Gerraty# value of the expression (which is usually an empty string) instead of the 239f45a3c8SSimon J. Gerraty# command that was executed. 24*22619282SSimon J. Gerraty# expect+1: warning: while evaluating "${:!echo word; (exit 13)!} != "word"" with value "word": Command "echo word; (exit 13)" exited with status 13 25*22619282SSimon J. Gerraty.if ${:!echo word; (exit 13)!} != "word" 26e2eeea75SSimon J. Gerraty. error 27e2eeea75SSimon J. Gerraty.endif 28*22619282SSimon J. Gerraty# expect+1: warning: while evaluating "${:Uprevious value:!echo word; (exit 13)!} != "word"" with value "word": Command "echo word; (exit 13)" exited with status 13 29*22619282SSimon J. Gerraty.if ${:Uprevious value:!echo word; (exit 13)!} != "word" 30e2eeea75SSimon J. Gerraty. error 31e2eeea75SSimon J. Gerraty.endif 32e2eeea75SSimon J. Gerraty 339f45a3c8SSimon J. Gerraty 34*22619282SSimon J. Gerraty.MAKEFLAGS: -dv # to see the "Capturing" debug output 35*22619282SSimon J. Gerraty# expect+1: warning: while evaluating "${:!echo word; ${:U(exit 13)}!}" with value "word": Command "echo word; (exit 13)" exited with status 13 36*22619282SSimon J. Gerraty_:= ${:!echo word; ${:U(exit 13)}!} 379f45a3c8SSimon J. Gerraty.MAKEFLAGS: -d0 389f45a3c8SSimon J. Gerraty 39*22619282SSimon J. Gerraty 402c3632d1SSimon J. Gerratyall: 41