Re: Automatically Handling Tools that Produce Many Outputs

[Bob Friesenhahn]

On Tue, 27 Nov 2007, Olly Betts wrote:
> My experience is that multi-output rules often aren't protected at all,
> and parallel make is unreliable on such projects.  This is becoming much
> more of an issue, as multicore boxes are now mainstream.

What relationship is there between parallel make and multicore? 
Parallel make has been in use long before most people had access to 
multiple CPUs.  Even with a single CPU, processes block waiting for 
I/O.

I definitely agree that all build paths need to be supported with a 
make rule.  Produced objects which are a side-effect of other rules 
cause problems for parallel builds.  Unfortunately, make itself is not 
very helpful here since it evaluates just one target at a time. 
Multiple products from a single input file can be a real problem, 
particularly if they are produced all at once (as is commonly done for 
IDL files).

Bob
======================================
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/