You should use the following steps for an async connect:
- create socket with
socket(..., SOCK_NONBLOCK, ...)
- start connection with
connect(fd, ...)
- if return value is neither
0
norEINPROGRESS
, then abort with error - wait until
fd
is signalled as ready for output - check status of socket with
getsockopt(fd, SOL_SOCKET, SO_ERROR, ...)
- done
No loops - unless you want to handle EINTR
.
If the client is started first, you should see the error ECONNREFUSED
in the last step. If this happens, close the socket and start from the beginning.
It is difficult to tell what's wrong with your code, without seeing more details. I suppose, that you do not abort on errors in your check_socket
operation.