> Patrick Mau <mau@oscar.prima.de> writes:
>
> > I wrote a little test program to do some poll() benchmarks.
> > I changed the host address to localhost and observed that
> > connect() always returns EINPROGRESS when used with non-blocking
> > sockets.
> >
> > >From the man page:
> >
> > EINPROGRESS
> > The socket is non-blocking and the connection cannot be completed
> > immediately. It is possible to select(2) or poll(2) for completion by
> > selecting the socket for writing.
> >
> > So my question is:
> >
> > What is meant by 'cannot be completed immediately' ?
> > I thought that connections to localhost would complete
> > without any delay when the application listens ?
>
> Probably the accept()ing process hasn't been scheduled yet.
> EINPROGRESS is a perfectly reasonable response in such a case.
You have to be prepared to handle both immediate and delayed
connection, especially if you want to be portable. (Solaris behaves
a bit differently than Linux in this regard.) See
http://www.kegel.com/dkftpbench/dkftpbench-0.37/ftp_client_pipe.cc
for an example of how to handle nonblocking connects more or less portably.
(You have to wade through quite a bit of code, tabstops 4, to find
all the connect-handling stuff -- sorry.)
- Dan
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This archive was generated by hypermail 2b29 : Tue Oct 23 2001 - 21:00:28 EST