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How do I copy or rewind *argv[]

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Top Forums Programming How do I copy or rewind *argv[]
# 8  
Old 08-03-2011
Code:
Accepting a file descriptor: Bad file descriptor
Select failed: Bad file descriptor

struct sockaddr_in serv;
struct sockaddr_in dest;
if ((simpleSocket=socket(AF_INET, SOCK_STREAM,0)) == -1)
if (bind(simpleSocket,(struct sockaddr *)&serv,sizeof(serv)) == -1)
if (listen(simpleSocket, 1000) == -1) 
if (select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1)
if (FD_ISSET(i, &read_fds))
newfd = accept(simpleSocket, (struct sockaddr *)&dest, NULL);

I thought that if I used a different struct with the accept that the network data would
be part of the (struct sockaddr_in dest). I also have couple more questions to ask
about network programming. Is there a way to receive from a network without stopping
a loop.
# 9  
Old 08-03-2011
Your problem is your third argument to accept(). Accept() wants the length of the structure (dest) in your case. You must pass a pointer to the length, so declare it first:

Code:
 socklen_t dlen;

Then assign and pass it:
Code:
dlen = sizeof( dest );
if( (newfd = accept( simpleSocket, (struct sockaddr *)&dest, &dlen )) < 0 )
       fprintf( stderr, "accept failed: %s\n", strerror( errno ) );

Quote:
Is there a way to receive from a network without stopping
a loop.
If you mean is there a way to test for data ready on any socket without blocking, yes. You can set a timeout on the select. If you set the value to zero, then the select call should return immediately and indicate which file descriptors are ready for non-blocking read. Have a very close look at the select() manual page.
# 10  
Old 08-03-2011
Re
Thanks for this coding.
# 11  
Old 08-03-2011
I used select with a time out value of 0 and I have a send command in my loop to see if
the data will be sent. I still have to send a return to the server before it will send data
the way I want it to. I'll post the whole loop because that might be the problem. Thanks much.
Code:
    for(;;)
    {
        read_fds = master;
        int i;
        if (select(fdmax+1, &read_fds, NULL, NULL, 0) == -1)
        {
            nonfatal("Select failed");
        }
        for(i = 0; i <= fdmax; i++)
        {            
            if (FD_ISSET(i, &read_fds)) // We got a connection
            {
                if (i == simpleSocket) {
                    // handle new connections
                    newfd = accept(simpleSocket, (struct sockaddr *)&inco, &clilen);

                    if (newfd == -1)
                    {
                        nonfatal("Accepting a file descriptor");
                    }
                    else 
                    {
                        FD_SET(newfd, &master); // add to master set
                        if (newfd > fdmax)      // keep track of the max
                        {
                            fdmax = newfd;
                        }
                        printf("New connection from %s on socket %d\n", inet_ntoa(inco.sin_addr), newfd);
                        const char welcome_message[] =
                        {
                            "Welcome: \r\n"
                            "Mud welcome goes here\r\n"
                        };
                        send(newfd, welcome_message, sizeof (welcome_message), 0);
                    }
                }
            }/* END FD_ISSET(i, &read_fds)*/            
        }/* for(i = 0; i <= fdmax; i++) */
                        int j;
                        if(ii<9000)    {ii++;}
                        sprintf(jog, "%d", ii);
                        for(j = 0; j <= fdmax; j++) {
                            // send to everyone!
                            if (FD_ISSET(j, &master)) {
                                    if (send(j, jog, sizeof jog, 0) == -1) {
                                        perror("send");
                                    }
                            }
                    }
    }/* END for(;;).*/

# 12  
Old 08-03-2011
Your select() statement is still not right. The last parameter is supposed to be a pointer to a timeval structure. Passing 0 (interpret as NULL in this case) indicates no timeout and the select will block until there is data for one of the filedescriptors.

Read the man page for select() -- it has a good example of how to use the timeout and illustrates the layout of the timevalue struct.
# 13  
Old 08-03-2011
Could you show me a proper select call?
# 14  
Old 08-04-2011
Quote:
Originally Posted by Errigour
Could you show me a proper select call?
Sure.

Code:
    struct timeval  delay;

    delay.tv_sec = 10;   /* seconds to delay */
    delay.tv_usec = 0;   /* micro seconds to delay */
    select( simpleSocket+1, &readfds, NULL, NULL, &delay)
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