On Thu, Jul 19, 2001 at 04:15:48PM -0400, Jeff Trawick wrote:
> On what platform do you see rv APR_SUCCESS/len 0 when there is nothing
> to read from the pipe?
>
> Ooh, Solaris does this!
Yup. I'm not insane. The POD doesn't work on Solaris without this
patch. =)
> Of course, it isn't the prettiest thing to implement. Here we're
> using a socket call (apr_recv) on a pipe :) Only the file code knows
> it is a pipe. You have to know it is a pipe to decide that rc==0 on
> such a platform means EAGAIN.
How do we test for this in autoconf (unless we specify something in
hints)?
In the threaded MPM, since we're specifying a timeout and that sets
O_NDELAY (we're setting O_NONBLOCK as well), we're hitting the
following clause in the Solaris read(2) manpage:
When attempting to read from an empty pipe (or FIFO):
o If no process has the pipe open for writing, read()
returns 0 to indicate end-of-file.
o If some process has the pipe open for writing and
O_NDELAY is set, read() returns 0.
o If some process has the pipe open for writing and
O_NONBLOCK is set, read() returns -1 and sets errno to
EAGAIN.
Hmm. And, this is tricky because we're referencing the POD as a socket
not as a file in the threaded MPM.
And, if we switch the threaded MPM to use the mpm_common code (treat
it as a file), we're not notified when we have an incoming POD signal
(like we are when we treat it as a socket). Ugh. Maybe we could do
both? Do the poll as a socket and read the POD as a file? -- justin
