[9fans] waitpid

[9fans] waitpid

[Joel Salomon]

I’m trying to wait for all child processes to finish.  The lunix code my professor gave me for this was:
	while (wait(&wstat)>0)
		;
which I naïvely translated as:
	while(waitpid() != 0)
		;
which hangs.  Evidently waitpid returns something other than 0 when there are no children, but what?  The man page wait(2) doesn’t say, nor does it point to the source for waitpid.

--Joel

Re: [9fans] waitpid

[Joel Salomon]

Never mind; I found /sys/src/libc/9sys/waitpid.c so I know that wait pid returns -1 if there are no children, and I’ve submitted a patch to wait(2).

--Joel

Re: [9fans] waitpid

[geoff]

Don't bother submitting a patch; I've updated the SOURCE section of
wait(2).  You didn't need the source to get the answer to your
question either; note the phrase `These routines set errstr.' and see
intro(2) for what this means.

Re: [9fans] waitpid

[Russ Cox]

> The man page wait(2) doesn't say,
> nor does it point to the source for waitpid.

The source for the entire C library is in /sys/src/libc/*/*.
It might take a few milliseconds to grep through.

Also:
http://www.google.com/search?q=plan9%20waitpid

Russ

Re: [9fans] waitpid

[Joel Salomon]

> The source for the entire C library is in /sys/src/libc/*/*.
> It might take a few milliseconds to grep through.

Plus a few seconds to open a window, type the grep command; compared to right-clicking in acme, it’s practically an eternity ☺.

--Joel

Re: [9fans] waitpid

[Joel Salomon]

> Don't bother submitting a patch; I've updated the SOURCE section of wait(2).

That was half my patch.

> You didn't need the source to get the answer to your question
> either; note the phrase `These routines set errstr.' and see
> intro(2) for what this means.

Is waiting without children considered an error condition?  Checking…
	waitpid returned -1: no living children
…looks like.  OK, a lack of understanding on my part; never mind.

--Joel

Re: [9fans] waitpid

[Bruce Ellis]

i good trick for finding a function's src is to run acid
on a program that uses it and ...

src(fname)

will you give you something which starts with a nice
plumbable string.

brucee

On 11/8/06, Joel Salomon <chesky@plan9.jp> wrote:
> > The source for the entire C library is in /sys/src/libc/*/*.
> > It might take a few milliseconds to grep through.
>
> Plus a few seconds to open a window, type the grep command; compared to right-clicking in acme, it's practically an eternity ☺.
>
> --Joel
>
>

Re: [9fans] waitpid

[Federico Benavento]

yep, like:

src -s fname binary

On 11/8/06, Bruce Ellis <bruce.ellis@gmail.com> wrote:
> i good trick for finding a function's src is to run acid
> on a program that uses it and ...
>
> src(fname)
>
> will you give you something which starts with a nice
> plumbable string.
>
> brucee
>
> On 11/8/06, Joel Salomon <chesky@plan9.jp> wrote:
> > > The source for the entire C library is in /sys/src/libc/*/*.
> > > It might take a few milliseconds to grep through.
> >
> > Plus a few seconds to open a window, type the grep command; compared to right-clicking in acme, it's practically an eternity ☺.
> >
> > --Joel
> >
> >
>


-- 
Federico G. Benavento

Re: [9fans] waitpid

[Bruce Ellis]

great, didn't know about that ... but i live in the past - the
rent is cheaper. one decade gdb will add some of its
obvious utility (blame it on bedbug if you like) but by then
it will be larger than all of plan9, if it isn't already.

brucee

On 11/8/06, Federico Benavento <benavento@gmail.com> wrote:
> yep, like:
>
> src -s fname binary
>
> On 11/8/06, Bruce Ellis <bruce.ellis@gmail.com> wrote:
> > i good trick for finding a function's src is to run acid
> > on a program that uses it and ...
> >
> > src(fname)
> >
> > will you give you something which starts with a nice
> > plumbable string.
> >
> > brucee
> >
> > On 11/8/06, Joel Salomon <chesky@plan9.jp> wrote:
> > > > The source for the entire C library is in /sys/src/libc/*/*.
> > > > It might take a few milliseconds to grep through.
> > >
> > > Plus a few seconds to open a window, type the grep command; compared to right-clicking in acme, it's practically an eternity ☺.
> > >
> > > --Joel
> > >
> > >
> >
>
>
> --
> Federico G. Benavento
>