See remarks below. EINVAL nfds is negative or exceeds the RLIMIT_NOFILE resource limit (see getrlimit(2)). See Limits on Resources, for details on the RLIMIT_NPROC limit. If not, and the connection attempt is still continuing, a timer is incremented and, after a small sleep, the connection will be polled again.This method makes heavy use of exception handling. click site
Is there a list of "official" port numbers? If the socket is connection oriented and the remote side has shut down the connection gracefully, and all data has been received, a recv will complete immediately with zero bytes received. Why not return 0? You have to make sure all the data is being sent, first of all. (See the sendall() function implementation for details.) Once you're sure of that, then you need to call http://stackoverflow.com/questions/2917881/how-to-implement-a-timeout-in-read-function-call
The function only returns messages from the remote address specified in the connection. This system call has somewhat different behavior from the glibc wrapper function. It return -1 on error, 0 on timeout or the number of file descriptors in the sets that are set. #include
The ppoll() system call was added to Linux in kernel 2.6.16. If you're building for Windows, you only need to #include
clientService.sin_family = AF_INET; clientService.sin_addr.s_addr = inet_addr( "127.0.0.1" ); clientService.sin_port = htons( 27015 ); //---------------------- // Connect to server. Check the manual for your particular platform. How do I build for Solaris/SunOS? http://man7.org/linux/man-pages/man2/select.2.html However, in the glibc implementation, the fd_set type is fixed in size.
Yes, you could convert your network clients into multithreaded applications, but often the amount of extra work required to do this is prohibitive. The data is copied into the buffer, but is not removed from the input queue. This error never occurs on GNU/Hurd systems. Naturally, this doesn't always work.
Concerning the types involved, the classical situation is that the two fields of a timeval structure are typed as long (as shown above), and the structure is defined in
How do I get a list of open sockets on the system? get redirected here Or, you could wrap the entire functionality in a single function, like this: #include
Executing FD_CLR() or FD_SET() with a value of fd that is negative or is equal to or larger than FD_SETSIZE will result in undefined behavior. The POSIX.1 situation is that one should include
The raw ppoll() system call has a fifth argument, size_t sigsetsize, which specifies the size in bytes of the sigmask argument. You could, for example, set the timeout to something low, like 500 ms, and update an indicator onscreen each timeout, then call select() again. How can I set a custom timeout value for a TCP or UDP socket?
The question was "How to implement a timeout?", not "What are some timeout considerations for general devices?" Good luck. –David C. The operation of select() and pselect() is identical, other than these three differences: (i) select() uses a timeout that is a struct timeval (with seconds and microseconds), while pselect() uses a Macro: int ECHILD There are no child processes. The following example shows just how easy it can be to handle timeouts, without resorting to multiple threads of execution:// Create a datagram socket on port 2000 to listen for incoming
Executing FD_CLR() or FD_SET() with a value of fd that is negative or is equal to or larger than FD_SETSIZE will result in undefined behavior. Users do not usually see this error because functions such as read and write translate it into a SIGTTIN or SIGTTOU signal. This could for example happen when data has arrived but upon examination has wrong checksum and is discarded. my review here Under glibc 2.1 to 2.2.1 it gives pselect() when _GNU_SOURCE is defined.
How do I input n repetitions of a digit in bash, interactively Is there a place in academia for someone who compulsively solves every problem on their own? The gist of it is that you make a socket descriptor with socket(), set it to non-blocking, call connect(), and if all goes well connect() will return -1 immediately and errno Return value If no error occurs, recv returns the number of bytes received and the buffer pointed to by the buf parameter will contain this data received. To do this, unset the ICANON flag, and set the VTIME control character: struct termios termios; tcgetattr(filedesc, &termios); termios.c_lflag &= ~ICANON; /* Set non-canonical mode */ termios.c_cc[VTIME] = 100; /* Set
The system tried to use the device represented by a file you specified, and it couldn’t find the device.