Re: patch to support output synchronization under -j

[Stefano Lattarini]

On Tuesday 03 May 2011, Paul Smith wrote:
> On Tue, 2011-05-03 at 09:48 +0200, Stefano Lattarini wrote:
> > > The other thing I was thinking is that this feature might want to be
> > > enabled via a command-line argument.  All the complex makefiles
> > > generated by automake, etc. for example cannot take advantage of this
> > > if you have to modify every makefile to add the special target.
> > > 
> > >
> > Not completely true.  A developer using Automake who wants to take
> > advantage of this feature could just add the line:
> >   .PARALLELSYNC:
> > to his Makefile.am file(s).  Automake's preprocessing policy is to
> > pass through the things it doesn't understand (or that are not
> > influential to it).
> 
> Sure, I realize that.  But that only helps developers.  I was thinking
> about users of open source software, building it on larger machines with
> -jN and wanted to get "clean" output when it fails.  That's my
> situation: I have archived vanilla tarballs downloaded directly from the
> upstream sites, and I have a makefile that does all that's necessary
> (unpack them, configure, build, install, etc.)
> 
> I certainly don't want to have to go modify the Makefile.am /
> Makefile.in files to get this feature enabled.
>
I agree with all of this; and in fact I'm all in favor of having a
command line switch to enable this new behaviour (like we currently
have both the `.SILENT' target and the `-s' switch).

I only have to point out (and sorry if I look picky/grumpy doing so) that
you'd have exactly the same kind of problems with "vanilla" packages using
hand-written Makefiles -- you'd still have to modify them by hand if you
want to get the new "outputsync" feature enabled.  The fact that a Makefile
has been written by hand or generated by Automake or CMake (or any other
proprocessors) is irrelevant in this regard.

> Also apropos of nothing, I don't like this name :-).  Maybe .OUTPUTSYNC
> or something would be better?  PARALLELSYNC doesn't help understand what
> the feature does.
>
`.OUTPUTSYNC' seems nicer indeed; but I'll leave it to you brave GNU make
maintainers to figure out the color of the shed ;-)  Once the new feature
is not active by default, I'll be happy.

Thanks,
   Stefano