If data is not available to the socket, and the socket is in blocking and synchronous modes, the READ call blocks the caller until data arrives. … The default mode of socket calls is blocking. A blocking call does not return to your program until the event you requested has been completed.

Are sockets blocking?

A socket can be in “blocking mode” or “nonblocking mode.” The functions of sockets in blocking (or synchronous) mode do not return until they can complete their action. This is called blocking because the socket whose function was called cannot do anything — is blocked — until the call returns.

Does accept () block?

accept() blocks (or, if you use a non-blocking listening socket, accept() succeeds) only when a new client connection is available for subsequent communication.