socket

This function creates a socket.

At a Glance

Header file:	Winsock.h
Windows CE versions:	1.0 and later

Syntax

SOCKET socket (int af, int type, int protocol);

Parameters

[in] Address family specification.

type

[in] Type specification for the new socket.

The following are the only two type specifications supported for Windows Sockets 1.1:

Value	Description
SOCK_STREAM	Provides sequenced, reliable, two-way, connection-based byte streams with an out-of-band data transmission mechanism. Uses TCP for the Internet address family.
SOCK_DGRAM	Supports datagrams, which are connectionless, unreliable buffers of a fixed (typically small) maximum length. Uses UDP for the Internet address family.

protocol

[in] Particular protocol to be used with the socket that is specific to the indicated address family.

Return Values

A descriptor referencing the new socket indicates that no error occurred. INVALID_SOCKET indicates failure. To get a specific error value, call WSAGetLastError.

Remarks

For Infrared Sockets (IrSock), this function has the following additional requirements:

Af_irda.h must be explicitly included.
Set the af parameter to AF_IRDA, and set the protocol parameter to NULL.

The PF_INET and AF_IRDA ARPA Internet address formats are supported.

The socket function causes a socket descriptor and any related resources to be allocated and bound to a specific transport service provider. Windows Sockets will utilize the first available service provider that supports the requested combination of address family, socket type and protocol parameters.

Connection-oriented sockets such as SOCK_STREAM provide full-duplex connections, and must be in a connected state before any data can be sent or received on it. A connection to another socket is created with a connect call. Once connected, data can be transferred using send and recv calls. When a session has been completed, a closesocket must be performed.

The communications protocols used to implement a reliable, connection-oriented socket ensure that data is not lost or duplicated. If data for which the peer protocol has buffer space cannot be successfully transmitted within a reasonable length of time, the connection is considered broken and subsequent calls will fail with the error value set to WSAETIMEDOUT.

Connectionless, message-oriented sockets allow sending and receiving of datagrams to and from arbitrary peers using sendto and recvfrom. If such a socket is connected to a specific peer, datagrams can be sent to that peer using send and can be received only from this peer using recv.