1# $NetBSD: deptgt-begin.mk,v 1.7 2023/06/01 20:56:35 rillig Exp $
2#
3# Tests for the special target .BEGIN in dependency declarations,
4# which is a container for commands that are run before any other
5# commands from the shell lines.
6
7# expect+2: warning: using previous script for ".BEGIN" defined here
8.BEGIN:
9	: $@
10
11# To register a custom action to be run at the beginning, the simplest way is
12# to directly place some commands on the '.BEGIN' target.  This doesn't scale
13# though, since the ':' dependency operator prevents that any other place may
14# add its commands after this.
15#
16# There are several ways to resolve this situation, which are detailed below.
17# expect+2: warning: duplicate script for target ".BEGIN" ignored
18.BEGIN:
19	: Making another $@.
20
21# One way to run commands at the beginning is to define a custom target and
22# make the .BEGIN depend on that target.  This way, the commands from the
23# custom target are run even before the .BEGIN target.
24.BEGIN: before-begin
25before-begin: .PHONY .NOTMAIN
26	: Making $@ before .BEGIN.
27
28# Another way is to define a custom target and make that a .USE dependency.
29# For the .BEGIN target, .USE dependencies do not work though, since in
30# Compat_MakeAll, the .USE and .USEBEFORE nodes are expanded right after the
31# .BEGIN target has been made, which is too late.
32.BEGIN: use
33use: .USE .NOTMAIN
34	: Making $@ from a .USE dependency.
35
36# Same as with .USE, but run the commands before the main commands from the
37# .BEGIN target.
38#
39# For the .BEGIN target, .USEBEFORE dependencies do not work though, since in
40# Compat_MakeAll, the .USE and .USEBEFORE nodes are expanded right after the
41# .BEGIN target has been made, which is too late.
42.BEGIN: use-before
43use-before: .USEBEFORE .NOTMAIN
44	: Making $@ from a .USEBEFORE dependency.
45
46all:
47	: $@
48
49_!=	echo : parse time 1>&2
50