Re: Parallel Make

[Ken Smith]

I'm not convinced that build systems would break if -j without arguments 
suddenly meant nothing instead of infinitely parallel.  The build would 
run serially but it would proceed correctly.  In my environment -j 
without arguments is invariably not what we want so if this doesn't get 
changed in gmake itself, I will end up patching it locally anyway.  I 
just hoped that others saw this as a flaw with -j and that it would be 
easy enough to fix.

However, that part of the discussion was an aside and my real concern is 
that I was actually giving an argument to -j which was ignored.  It is 
not always ignored but in 10 builds it was ignored 5 times.  When "-j 4" 
is the first argument on the command line it never happens.  When it 
appears after a variable assignment it happens occasionally.  Any ideas?

Ken

Tristan Van Berkom wrote:

> Noel Yap wrote:
>
> > I agree that a lone -j shouldn't default to infinity for practical 
> > reasons.  OTOH, a default of 1 would make the flag meaningless and a 
> > default of 2 seems unclean to me.  IMHO, -j shouldn't have a default 
> > at all.  Further, for those that like the infinite behaviour, I think 
> > allowing --jobs=infinity would help curb such an appetite a little.
>
>
>     Hmmm, the same could be said about the unix open system call; why
> should i have to open a named pipe in read/write if I dont want to 
> block ?
> why not throw non-blocking behavior on as default and add a O_BLOCK flag
> instead ?
>
> Ok, so its a bad example; but what I'm getting at is that you cant just
> modify the expected behavior of the open() system call because everyone's
> code will instantly break, much in the same way as IMO, many build
> systems will break when you change the expected behavior of GNU make.
>
> If everyone is bent on changing that behavior, why not add something new
> like `-J' which behaves exactly like `-j' but with a different default
> behavior ?
>
> My casual too sence ;-)
>
> Cheers,
>                                          -Tristan