On Tuesday 21 June 2011, Ralf Wildenhues wrote:
> * Stefano Lattarini wrote on Mon, Jun 20, 2011 at 10:58:05PM CEST:
> > On Monday 20 June 2011, Ralf Wildenhues wrote:
> > > For example the parallel BSD makes tend to reuse shells for running
> > > the recipe commands;
> > >
> > But only for the commands in the same recipe, right?
>
> I think not.
>
This example seems to show otherwise, luckily:
$ cat Makefile
all: a b c d
a b c d:
@exec echo seen-$@
@echo unseen-$@
$ make -j4
--- a ---
--- b ---
--- c ---
--- d ---
--- a ---
seen-a
--- b ---
seen-b
--- c ---
seen-c
--- d ---
seen-d
Tested on NetBSD 5.1 with system make, and on Debian with netbsd-make
and freebsd-make.
And in fact, quoting the Autoconf manual:
`` Support for parallel execution in make implementation varies.
Generally, using GNU make is your best bet. When NetBSD make
is invoked with -jN, it will reuse the same shell for multiple
commands *within one recipe*. ''
(emphasis added by me above)
> > > I'm not so sure they like if their shells go away with exec.
> > >
> > In this case, not a problem I think, since the invocation of the
> > testsuite driver is the last command in the recipe.
>
> Well, they should cope with it anyway, and use a new shell if the old
> one is gone.
>
Agreed. Still, as shown above, in this case that bug-like feature
shouldn't come to bite us.
Regards,
Stefano
