Programming

Excellent, good to hear.

Again, do this step by step. You should

(a) have the socket in non-blocking mode.

(b) add lots of tracing and debugging code so you can print out what is actually happening

(c) you *must* cater for partial reads, where you try and read 100 bytes and only get 50.

You should be able to have many very long running client connections.

sir,

that I am doing correctly.....

I am only having one client attached to the server.....(acc to my system).

first of all I starts my server.....and from another system I starts client ....now connection got established after that client tries to send sone data...my server recieves it correctly(I am using client fd to collect what server is sending)....after that when client tries to send some more packets or data then it fails ......means its polls only once.....after that it doesnt read any packet......
please tell me which file drscriptor should i use to read and send data......

In pseudo code-


int fd_server=socket(AF_INET,SOCK_STREAM,0);
bind(fd_server,...
listen(fd_server,..

when socket fd_server is readable do

fd_client=accept(fd_server,...)

then use the fd_client to send() and recv() on, and finally close() when you are finished with that client.

While you have one client, another client can come in and try and connect, so hence you need to work out how to accept and manage multiple client connections each with their own file descriptor.

Thanks Sir,
my both -----Socket part and Pipe & message queue part are working correctly.....
thanks a lot for ur precious help.....

Excellent, I am glad to hear of your success.

Hi All,

I am doing the same task of sending and receiving the messages through SOCKETS and writing back to files using message ques.

Please guide me how to get rid :

msgrcv : Invalid argument.

I am using message queues: msgsnd and msgrcv,

I am able to send through msgsnd and receive through msgrcv, but at times i get the belo error.

msgrcv : Invalid argument.

Snippet from the man page.

Code:

int msgrcv(int msqid, void *msgp, size_t msgsz, long msgtyp, int msgflg);
  The msgrcv() function will fail if:

     [EINVAL]           The msqid argument is not a valid message queue iden-
                        tifier.

                        The message queue was removed while msgrcv() was wait-
                        ing for a message of the requested type to become
                        available on it.

                        The msgsz argument is less than 0.

One of these is the culprit.