Subj : Re: IOCP problem
To   : comp.programming.threads
From : Richard Hollis
Date : Sun Jan 30 2005 09:04 pm

Thank you for taking the time to respond on this.

Is there a good book you can recommend on general do's and don'ts and good
practices?

Thanks
Richard

"SenderX" <xxx@xxx.com> wrote in message
news:7OGdnW_5fNnn1GXcRVn-hw@comcast.com...
>
> "SenderX" <xxx@xxx.com> wrote in message
> news:YuSdnX08G6Bg22XcRVn-rg@comcast.com...
> > Go ahead and try something like this:
>
> If found a NASTY race-condition:
>
>
>
> >        if ( ! ReadFile
> >                ( hPipe,
> >                  &read_buffer,
> >                  PIPE_MSG_MAX,
> >                  &dwBytesRead,
> >                  lpo ) )
> >        {
> >          DWORD err = GetLastError();
> >
> >          if ( err != ERROR_IO_PENDING )
> >          {
> >            TRACE1("ReadFile dwLastErr = %d\n", err );
> >            DisconnectNamedPipe( hPipe );
> >            ConnectNamedPipe( hPipe, lpo );
> >            state = 0;
> >            continue;
> >          }
> >        }
> >
> >        ++state;
>
> ++state is racing with another thread that could dequeue the OVERLAPPED.
You
> MUST set the state "before you enqueue a completion"!
>
>
> Something like this:
>
>
>
>       if ( ! state )
>       {
>         ++state; // BEFORE we enqueue
>
>         if ( ! ReadFile
>                 ( hPipe,
>                   &read_buffer,
>                   PIPE_MSG_MAX,
>                   &dwBytesRead,
>                   lpo ) )
>         {
>           DWORD err = GetLastError();
>
>           if ( err != ERROR_IO_PENDING )
>           {
>             TRACE1("ReadFile dwLastErr = %d\n", err );
>             DisconnectNamedPipe( hPipe );
>             ConnectNamedPipe( hPipe, lpo );
>             state = 0;
>             continue;
>           }
>         }
>       }
>
>       else if ( state == 1 )
>       {
>         ++state; // BEFORE we enqueue
>
>         if ( ! WriteFile
>                 ( hPipe,
>                   "OK",
>                   3,
>                   &dwBytesWritten,
>                   lpo ) )
>         {
>           DWORD err = GetLastError();
>
>           if ( err != ERROR_IO_PENDING )
>           {
>             TRACE1("WriteFile dwLastErr = %d\n", err );
>             DisconnectNamedPipe( hPipe );
>             ConnectNamedPipe( hPipe, lpo );
>             state = 0;
>             continue;
>           }
>         }
>       }
>
>

.