Re: pthreads & sockets

From: David Schwartz (davids_at_webmaster.com)
Date: 09/03/03 

Date: Wed, 3 Sep 2003 14:28:18 -0700

>2. Again there a two threads and one socket. The first thread opens the TCP
> connection, then the second thread executes a blocking recv() on the
same
> socket. At some time later, the first thread closes the socket (by
> calling close()). I would expect the recv() to return control, but it
> doesn't.

    You must not do this. The problems have been discussed in this newsgroup
many times. The problem is that it is impossible to be 100% sure the other
thread is in 'recv' when you call 'close'. It could be about to call 'recv'.

    DS

Relevant Pages

  • Re: Synchronization with CAsyncSocket in CE 6.0
    ... number of bytes in the first packet, followed by packets of, say 1024 bytes. ... recv() operations, reassembling it into the format that you need. ... don't forget that recv can return zero, if the socket has ... So, CAsyncSocket while possibly a bad way to do things, does not appear to ...
    (microsoft.public.windowsce.embedded)
  • Re: Receive no data
    ... It is a best practice to shutdown ... a socket for sending once all data has been sent. ... I see multiple recv() statements in the code. ...
    (microsoft.public.win32.programmer.networks)
  • RE: BUG in Winsock on P4 HT CPU
    ... If you read the help on WSAAsyncSelect it states ... Network transport stack receives 100 bytes of data on socket s and causes ... The application issues recv(s, buffptr, 50, 0) to read 50 bytes. ... on CPU's that do not support HT, or CPUs with HT disabled. ...
    (microsoft.public.win32.programmer.networks)
  • Re: recv() hangs until SIGCHLD ?
    ... Both lsof and ls /proc//fd show that the socket used is in ESTABLISHED mode but when checking on the host on which it's connected we can't find the corresponding client socket. ... We are correctly handling EINTR in sendand recv() by restarting the call in case they get interrupted this way. ... However since this problem does not occur without threads, we can be sure that the blame is still on the receiver. ... In a practical case, we have a thread blocked in recvfor more than 12 hours, which is way beyond the timeout of the sender connection. ...
    (Linux-Kernel)
  • Re: how to avoid recv() blocking issue?
    ... using WSAEventSelect. ... we have a weak link in a chain: a timeout. ... drop the connection abnormally such that the blocking recv will never ... TerminateThread- btw, it's not a good idea, because a socket ...
    (microsoft.public.win32.programmer.networks)