33 lines
1.0 KiB
Makefile
33 lines
1.0 KiB
Makefile
# $NetBSD: varmod-shell.mk,v 1.6 2021/02/14 20:16:17 rillig Exp $
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#
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# Tests for the ':!cmd!' variable modifier, which runs the shell command
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# given by the variable modifier and returns its output.
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#
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# This modifier has been added on 2000-04-29.
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#
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# See also:
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# ApplyModifier_ShellCommand
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# The command to be run is enclosed between exclamation marks.
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# The previous value of the expression is irrelevant for this modifier.
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# The :!cmd! modifier turns an undefined expression into a defined one.
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.if ${:!echo word!} != "word"
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. error
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.endif
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# If the command exits with non-zero, an error message is printed.
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# XXX: Processing continues as usual though.
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#
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# Between 2000-04-29 and 2020-11-17, the error message mentioned the previous
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# value of the expression (which is usually an empty string) instead of the
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# command that was executed. It's strange that such a simple bug could
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# survive such a long time.
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.if ${:!echo word; false!} != "word"
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. error
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.endif
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.if ${:Uprevious value:!echo word; false!} != "word"
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. error
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.endif
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all:
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