How to reconnect the clients to server?

Question

My server program (socket stream) is running and it accepts the clients. Due to some abnormal condition, server is getting terminated. The other side clients are waiting for server reply. How to I reconnect the running clients to new server? any functions in sockets?

Answer 1

A socket that had been connect()ed once cannot be reused with another call to connect().

The steps to connect to a TCP server and read/write some data are as follows (pseudo code):

sd = socket(...) // create socket descriptor (allocate socket resource)
connect(sd, server-address, ...) // connect to server
read/write(sd, data)  // read from server 
close(sd) // close /socket descriptor (free socket resource)

In case the server goes down after connect all the client could and shall do is

close(sd) // close socket descriptor (free socket resource)

and then start over beginning with:

sd = socket(...) // create socket descriptor (allocate socket resource)
...

Starting over beginning with:

connect(sd, server-address, ...) // connect to server
...

would probably lead to undefined behaviour, but at least to an error.