make: multiple dependency lines and ..

[Hans Buurman]

I complained the other day about make, multiple dependency lines
and .. . I got one reply from Bradley White (bww at mtxinu.com),
which seems only appropriate to share with the net:

} The problem in your case though is with code to handle double suffix
} rules like:
} 
} 	.c.o:
} 		cc -c $*.c
} 
} In order to make it possible to redefine these rules, make throws
} away all but the last command set for any target that begins with '.'.
} 
} So in your case
} 
} 	../dir/foo:
} 		touch file1 ../dir/foo
} 
} 	../dir/foo: file1
} 
} turned into
} 
} 	../dir/foo:
} 
} 	../dir/foo: file1
} 
} and so nothing was ever executed.
} 
} The fix?  Well, seeing as you can only ever have one rule set on
} a ':' target anyway, just make sure it is the last one.  That is,
} 
} 	../dir/foo: file1
} 
} 	../dir/foo:
} 		touch file1 ../dir/foo
} 
} will work just fine.
} 
(...)
} 
} I too consider the behaviour an aberration, and have proposed changing
} the rule for discarding previous command sets to "begins with a '.'
} AND doesn't contain a '/'" --- a suffix rule should never have a '/'.

Thanks to Bradley White for pointing this out. We agreed that it was
a bug indeed.

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Hans Buurman                   | hans at duttnph.tudelft.nl
Pattern Recognition Group      | hans at duttnph.UUCP
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