How to detect whether socket is still connected...

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How to detect whether socket is still connected…



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From wget source code…

bool
test_socket_open (int sock)
{
fd_set check_set;
struct timeval to;
int ret = 0;

/* Check if we still have a valid (non-EOF) connection.  From Andrew
* Maholski's code in the Unix Socket FAQ.  */

FD_ZERO (&check_set);
FD_SET (sock, &check_set);

/* Wait one microsecond */
to.tv_sec = 0;
to.tv_usec = 1;

ret = select (sock + 1, &check_set, NULL, NULL, &to);
#ifdef WINDOWS
/* gnulib select() converts blocking sockets to nonblocking in windows.
wget uses blocking sockets so we must convert them back to blocking
*/
set_windows_fd_as_blocking_socket ( sock );
#endif

if ( !ret )
/* We got a timeout, it means we're still connected. */
return true;
else
/* Read now would not wait, it means we have either pending data
or EOF/error. */
return false;
}

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