Re: Improvement on parallel make

[Brendan Heading]

Alexey Neyman wrote:

> <<<
> foo: bar .WAIT baz
> fum: bar boo
> fun: baz buu
> <<<
>
> the command "make -j 4 fum fun" will still serialize the "bar" and 
> "baz" targets, with "bar" completed before "baz" is started. Note 
> that the targets command line does not include "foo" - which 
> specifies the .WAIT behavior.

Further to my reply to Philip earlier, why would bar and baz need to be 
serialized in the first place unless there was a dependency ? And if 
there is a dependency, why would someone chose to use this syntax rather 
than making that dependency explicit in the Makefile ?

> BSD make behaves so, because it records the "bar" target as a 
> predecessor for the "baz" target. If both targets are to be remade, 
> they will be serialized. If only one is to be remade, there will be 
> no serialization imposed.

Is this an attempt to try to make GNU make compatible with BSD make ? I 
do not believe that alone is sufficient justification for introducing a 
measure that appears to exist only to work around the fact that some 
people may not understand how to define dependencies correctly in their 
makefiles.

It would be interesting to hear of some real-world cases involving 
valid/recommended uses of Make, which require this suspicious-looking 
syntax.