Yeah I think is perfectly normal Select will unblock in only one of the threads.. (Usually this done )1) What u can do is have a master thread bind and listen to the socket + port and then depending on ur need u can spawn threads to perfom operations on the data. If however u need interface level multiplexing of socket what u can do is use SO_REUSEADDR option and create alias to ur socket address (using ifconfig)and then bind on different sockt address alias but on same port. That way two threads will listen to (actually )socket address but different alias. regards divyank --- Manjunath Naik <peter.desouzain@xxxxxxxxx> wrote: > On 5/19/06, tyler@xxxxxxxx <tyler@xxxxxxxx> wrote: > > > > On Wed, May 17, 2006 at 09:59:38PM -0700, vikram b > wrote: > > > Hi All, > > > I dont know whether this is right > place to put this ( Pls > > suggest if > > > anybody know correct place) > > > I am trying to use select system call to read > from network socket. I > > have > > > opened a socket and bind it on a port > > > I have two threads (user space) each having a > select , who is waiting on > > same > > > Socket FD. > > > When i send any data , only one of the thread is > getting the data ... > > > Is it normal ? Can i have any ways to have data > to both select ? > > > > > > Any suggestion will be of great help > > > > > > > > > thanks in advance > > > > > > vikram > > > > > Hi, > > > > yes, it's normal. It's not the goal of select. > > > > In fact, in your case, what you do is just reading > from the socket in a > > thread. The data is taken from the socket. Then > the other do another > > read and there's no data. > > > > If you want the data to be received by the two > processes, you should > > share it (threads have the same adress space, it's > easy to do without > > any mechanism). > > > > In your case, if 2 threads want the data received > (let's say thread A > > and thread B), you should do 3 threads : > > the first thread which just reads from the socket. > When data is > > received, it wakes up threads A and B. > > > > > > -- > > tyler > > tyler@xxxxxxxx > > > > > I agree with tyler. I am not able to understand why > in two threads you want > to wait on same socket descriptor? > > Once the data has been read from the socket it has > been removed from the > buffer. > > since you are working with threads and both run on > the same address process, > i think you can shared the data between them once > one of the threads reads > it though notification mechanism. > > I think theoritically it may possible with only two > thread also. Whenever > one thread receives the data let it notify other > thread. I am not sure > whether it is possible practically. If I am wrong > Please correct me tyler. > > Thanks > Manjunath Naik > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
