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