Re: strange dependancy generation bug?

Stig Brautaset (stig@brautaset.org)
Tue, 3 Jun 2003 21:06:29 +0100


On Jun 03 2003, Sam wrote:
> On Tue, Jun 03, 2003 at 08:11:54PM +0100, Stig Brautaset wrote:
> > > What happens is that within Makefile.build there is used multi line
> > > definition, where each new-line causes make to launch a new sub-shell.
> > > The command for the second sub-shell is echoed, even though make is told
> > > not to do so.
> >
> > I beg to differ. Since make launches a new subshell, the commands in the
> > second subshell is _not_ told to shut up, and thus is echoed. No?
>
> In make a so-called "canned command sequence" is generated.
> Quote from 'info make':
>
> On the other hand, prefix characters on the command line that refers
> to a canned sequence apply to every line in the sequence. So the rule:
>
> frob.out: frob.in
> @$(frobnicate)
>
> does not echo _any_ commands.
>
>
> In kbuild this is exactly what happens.
> So according to make info the command for the second sub-shell should not
> be echoed.

Indeed. It seem I haven't read the docs carefully enough. I was just
looking at cause and effect -- not how it's _supposed_ to work. ;)

Here, with two subshells, the latter part is echoed, with one it is not.
However, in the light of this (to me) new information I'm at a loss as
to what causes this to happen.

Stig

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brautaset.org
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