48 lines
1.6 KiB
Makefile
48 lines
1.6 KiB
Makefile
# $NetBSD: deptgt-begin.mk,v 1.6 2022/05/07 08:01:20 rillig Exp $
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#
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# Tests for the special target .BEGIN in dependency declarations,
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# which is a container for commands that are run before any other
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# commands from the shell lines.
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.BEGIN:
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: $@
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# To register a custom action to be run at the beginning, the simplest way is
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# to directly place some commands on the '.BEGIN' target. This doesn't scale
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# though, since the ':' dependency operator prevents that any other place may
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# add its commands after this.
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#
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# There are several ways to resolve this situation, which are detailed below.
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.BEGIN:
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: Making another $@.
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# One way to run commands at the beginning is to define a custom target and
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# make the .BEGIN depend on that target. This way, the commands from the
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# custom target are run even before the .BEGIN target.
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.BEGIN: before-begin
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before-begin: .PHONY .NOTMAIN
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: Making $@ before .BEGIN.
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# Another way is to define a custom target and make that a .USE dependency.
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# For the .BEGIN target, .USE dependencies do not work though, since in
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# Compat_MakeAll, the .USE and .USEBEFORE nodes are expanded right after the
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# .BEGIN target has been made, which is too late.
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.BEGIN: use
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use: .USE .NOTMAIN
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: Making $@ from a .USE dependency.
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# Same as with .USE, but run the commands before the main commands from the
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# .BEGIN target.
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#
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# For the .BEGIN target, .USEBEFORE dependencies do not work though, since in
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# Compat_MakeAll, the .USE and .USEBEFORE nodes are expanded right after the
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# .BEGIN target has been made, which is too late.
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.BEGIN: use-before
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use-before: .USEBEFORE .NOTMAIN
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: Making $@ from a .USEBEFORE dependency.
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all:
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: $@
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_!= echo : parse time 1>&2
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