50 lines
1.6 KiB
Makefile
50 lines
1.6 KiB
Makefile
# $NetBSD: deptgt.mk,v 1.11 2021/04/04 10:13:09 rillig Exp $
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#
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# Tests for special targets like .BEGIN or .SUFFIXES in dependency
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# declarations.
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# TODO: Implementation
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# Just in case anyone tries to compile several special targets in a single
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# dependency line: That doesn't work, and make immediately rejects it.
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.SUFFIXES .PHONY: .c.o
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# The following lines demonstrate how 'targets' is set and reset during
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# parsing of dependencies. To see it in action, set breakpoints in:
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#
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# ParseDependency at the beginning
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# FinishDependencyGroup at "targets = NULL"
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# Parse_File at "Lst_Free(targets)"
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# Parse_File at "targets = Lst_New()"
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# ParseLine_ShellCommand at "targets == NULL"
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#
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# Keywords:
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# parse.c:targets
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target1 target2: sources # targets := [target1, target2]
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: command1 # targets == [target1, target2]
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: command2 # targets == [target1, target2]
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VAR=value # targets := NULL
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: command3 # parse error, since targets == NULL
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# In a dependency declaration, the list of targets can be empty.
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# It doesn't matter whether the empty string is generated by a variable
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# expression or whether it is just omitted.
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.MAKEFLAGS: -dp
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${:U}: empty-source
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: command for empty targets list
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: empty-source
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: command for empty targets list
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.MAKEFLAGS: -d0
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# Just to show that a malformed expression is only expanded once in
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# ParseDependencyTargetWord. The only way to produce an expression that
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# is well-formed on the first expansion and ill-formed on the second
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# expansion would be to use the variable modifier '::=' to modify the
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# targets. This in turn would be such an extreme and unreliable edge case
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# that nobody uses it.
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$$$$$$$${:U:Z}:
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all:
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@:;
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