Previous

Next

Function bind

Bind a socket to a local port number and IP address.

int bind(SOCKET socket, const struct sockaddr * addr, int * addrlen);

Parameters

socket

Socket returned by socket.

addr

IP address and port number to associate with the socket. Port number and IP address are in network byte order. This parameter has type struct sockaddr * for historical reasons. Use type struct sockaddr_in * instead.

addrlen

Pointer to length of valid information in addr.

return value

Returns 0 if successful, otherwise SOCKET_ERROR. If an error occurred, call xn_getlasterror and xn_geterror_string to return the error value. Section Error Codes further describes each error. Possible values for this function are:

This routine attaches a specific input port number and IP address to an unconnected socket. For TCP, it is called before listen/accept. Server applications will call bind to establish a well known port for clients to call on. bind does not establish any connections itself. If bind is called with INADDR_ANY for its IP address, packets from any of its interfaces are accepted. If bind is called with 0 for its port number, the system assigns a unique port number.

For UDP and RAW, in order to receive broadcasts, the socket should be bound to INADDR_ANY or to the broadcast address. To receive multicasts, you can bind to the local IP address, INADDR_BROADCAST, or to the multicast address. You may also bind to INADDR_ANY to receive all packets sent to a specific port number.

It is not necessary to call bind. If connect or sendto is called and bind has not been called, an implicit bind is done with a random port number in the range 1024 to 5000 and the local IP address associated with the same interface connect or sendto is using.

Socket API

Function accept

Function closesocket