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1b65f0bd2b
o allow env var MAKE_OBJDIR_CHECK_WRITABLE=no to skip writable checks in InitObjdir. Explicit .OBJDIR target always allows read-only directory. o Fix building and unit-tests on non-BSD. o More code cleanup and refactoring. o More unit tests
28 lines
1 KiB
Makefile
28 lines
1 KiB
Makefile
# $NetBSD: var-op-expand.mk,v 1.4 2020/11/08 14:00:52 rillig Exp $
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#
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# Tests for the := variable assignment operator, which expands its
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# right-hand side.
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# TODO: Implementation
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# XXX: edge case: When a variable name refers to an undefined variable, the
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# behavior differs between the '=' and the ':=' assignment operators.
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# This bug exists since var.c 1.42 from 2000-05-11.
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#
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# The '=' operator expands the undefined variable to an empty string, thus
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# assigning to VAR_ASSIGN_. In the name of variables to be set, it should
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# really be forbidden to refer to undefined variables.
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#
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# The ':=' operator expands the variable name twice. In one of these
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# expansions, the undefined variable expression is preserved (controlled by
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# preserveUndefined in VarAssign_EvalSubst), in the other expansion it expands
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# to an empty string. This way, 2 variables are created using a single
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# variable assignment. It's magic. :-/
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.MAKEFLAGS: -dv
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VAR_ASSIGN_${UNDEF}= undef value
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VAR_SUBST_${UNDEF}:= undef value
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.MAKEFLAGS: -d0
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all:
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@:;
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