> From: Justin Erenkrantz [mailto:[EMAIL PROTECTED]
>
> On Fri, Jul 05, 2002 at 08:47:32PM -0400, [EMAIL PROTECTED] wrote:
> > This also creates a support library for APR, this is basically just
a
> > series of functions that APR can use internally to get the job
> > done. Since wait_for_io_or_timeout was identical between files and
> > sockets, I have moved that function to the support lib, it also now
uses
> > apr_poll().
>
> What's the rationale behind a 'support library' for APR? All of the
> content in newpoll.tar.gz seems like it should just stay in APR. You
> have me thoroughly confused here. Perhaps in a new directory, but
> definitely not a separate library.
Support library may have been the wrong words. It is just a set of
functions for use inside of APR that don't belong to any other category
of APR functions. It is implemented as a directory inside of APR, but
the functions aren't meant to be used outside of APR.
> I'm also not clear what the additional num parameter to apr_poll is
> buying us. Why not just use the *nsds value on input as your num
> parameter? The number of descriptors read is what *nsds is on the
> output. No signature change required.
Because if Apache can't get it right, then I am assuming that nobody
else can either. I had originally coded it to use *nsds just as you
describe below, and it didn't pass any tests, because throughout the
code people were passing 0 as *nsds. I decided to fix an API problem
that I created years ago by using the same variable for both input and
output parameters in this patch. I am not tied to adding num, but I do
believe that it is the correct approach.
> So, why not do something like this (very rough):
>
> (Some OS does the low magic number off the stack, but I can't
> remember which for the life of me.)
>
> apr_status_t apr_poll(apr_pollfd_t *aprset, apr_int32_t *nsds,
> apr_interval_time_t timeout)
> {
> int i, rv;
> struct pollfd *pollset;
> struct pollfd stack_pollset[SOME_LOW_MAGIC_NUMBER_LIKE_SAY_6];
The small array on the stack is an optimization that I was discussing
with bpane last night. It would require some testing to find the right
number, and I wasn't ready to do that. I wanted to get the
implementation out there, and I figured we could continue to optimize it
once it was done.
Ryan
