recv timeout

[Steve Holle]

The following snip was lifted from and excellent tutorial titled "Beej's 
Guide to Network Programming Using Internet Sockets" by Brian "Beej" Hall 
and can be downloaded in many formats at :

http://www.ecst.csuchico.edu/~beej/guide/net/

Short but very useful.

         int RecvTimeout ( int s, char *buf, int len, int timeout )
         {
                 fd_set fds ;
                 int n ;
                 struct timeval tv ;

                 // Set up the file descriptor set.
                 FD_ZERO(&fds) ;
                 FD_SET(s, &fds) ;

                 // Set up the struct timeval for the timeout.
                 tv.tv_sec = timeout ;
                 tv.tv_usec = 0 ;

                 // Wait until timeout or data received.
                 n = select ( s+1, &fds, NULL, NULL, &tv ) ;
                 if ( n == 0  ) return -2 ;                      // Timeout
                 if ( n == -1 ) return -1 ;                      // Error

                 // data must be here, so do a normal recv
                 return recv ( s, buf, len, 0 ) ;
         }

         static void TelnetReadTask (rtems_task_argument fd)
         {
           rtems_unsigned32 count ;

                 char cbuf[512];
                 int n;
                 rtems_status_code sc;
           char buffer [ MAX_RLC_IN_MESSAGE_SIZE+1 ];                // 
plus 1 to leave space for the NULL terminator
           rtems_unsigned32 size ;
           rtems_unsigned32 i ;
           int j;


                 for (;;)
                 {
                         n = RecvTimeout ( fd, cbuf, sizeof(cbuf), 
READ_TIMEOUT_IN_SECONDS ) ;

                         if                      ( n == 0 )
                         {
                                 TelnetConnected = false ;
               telnet_server_ts_cout << "Telnet closed by remote port." << 
std::endl ;
                                 break;
                         }
                         else if ( n == -1 )
                         {
                                 TelnetConnected = false ;
               telnet_server_ts_cout << "Telnet closed by timeout." << 
std::endl ;
                                 break;
                         }
                         else if ( n == -2 )
                         {
                                 TelnetConnected = false ;
               telnet_server_ts_cout << "Telnet closed by error." << 
std::endl ;
                                 break;
                         }
                         else    // Valid data in buffer
                 telnet_server_2_rlc_queue_send ( cbuf, n ) ;
                 }
                 if (close (fd) < 0)
       telnet_server_ts_cout << "Telnet close Error." << std::endl ;
                 sc = rtems_task_delete (RTEMS_SELF);
     telnet_server_ts_cout << "Telnet task delete Error." << std::endl ;
         }


At 01:09 PM 9/26/2004, Angelo Fraietta wrote:

>Eric Norum wrote:
>
>>
>>On Sep 24, 2004, at 11:57 AM, Steve Holle wrote:
>>
>>>I have a simple socket application and I would like to timeout recv 
>>>after a fixed period of inactivity.  I found an article showing how to 
>>>do it using select but I am under the impression this is not supported.
>>>
>>>What would be the best way to accomplish the timeout.
>>
>>
>>select() works with sockets, but is a very expensive call.  A better 
>>technique is to use the SO_RCVTIMEO socket option.
>
>Do you have an example or code snippet using it?.
>
>--
>Angelo Fraietta
>
>PO Box 859
>Hamilton NSW 2303
>
>Home Page
>
>
>http://www.users.bigpond.com/angelo_f/
>
>There are those who seek knowledge for the sake of knowledge - that is 
>CURIOSITY
>There are those who seek knowledge to be known by others - that is VANITY
>There are those who seek knowledge in order to serve - that is LOVE
>    Bernard of Clairvaux (1090 - 1153)
>
>

Steve Holle
Link Communications, Inc.
1035 Cerise Rd.
Billings, MT  59101
sholle at link-comm.com