Socket Accept Function Explained

In network programming, the accept() function of Socket is a blocking function used to accept client connection requests and create a new Socket object to handle communication with the client.

The prototype for the accept() function is as follows:

int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);

Explanation of Parameters:

1. Sockfd is the socket file descriptor for the server side, used to listen for client connection requests.
2. The addr pointer points to a struct sockaddr type, used to store the client’s address information.
3. addrlen is a pointer to a socklen_t type, used to specify the length of addr, and after the accept function is called, it returns the actual length of the client’s address.

The function will return a new Socket file descriptor for communicating with the client. This descriptor is separate from the original listening Socket file descriptor and is specifically for communicating with that client. If an error occurs, it will return -1.

The workflow of the accept() function is as follows:

1. A server-side program uses the socket() function to create a socket file descriptor, and then uses the bind() function to associate it with a local address.
2. The server calls the listen() function on the socket to set it to a listening state, waiting for connection requests from clients.
3. The client invokes the connect() function to establish a connection with the server-side socket.
4. After the server-side Socket detects a connection request from the client, it calls the accept() function to accept the request and creates a new Socket file descriptor to communicate with the client.
5. The server side can use a new socket file descriptor to communicate with the client while still listening on the original socket file descriptor for other client connection requests.

It is important to note that the accept() function will block the program’s execution until a client connection request arrives. If you want to perform other operations while waiting for connection requests, you can use non-blocking sockets or handle connection requests with multiple threads/processes.