connect function (winsock)

Establishes a connection to a specified socket.

Syntax

int connect(
    SOCKET s,
    const struct sockaddr *name,
    int namelen
);

Parameters

Parameter	Description
`s`	Descriptor identifying the socket to be connected.
`name`	Pointer to a `sockaddr` structure that contains the address of the target socket.
`namelen`	Length, in bytes, of the address pointed to by `name`.

Return Value

If the function succeeds, 0 is returned. On error, -1 is returned and WSAGetLastError() provides extended error information.

Remarks

The connect function is used by a client socket to establish a connection to a server socket. For connection-oriented protocols (e.g., TCP), this initiates the three-way handshake. For connectionless protocols (e.g., UDP), connect merely sets a default remote address for subsequent send and recv calls.

Example

Example: Connecting to a TCP server

#include <winsock2.h>
#include <ws2tcpip.h>
#pragma comment(lib, "Ws2_32.lib")

int main() {
    WSADATA wsaData;
    SOCKET ConnectSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL, hints;
    const char *sendbuf = "Hello, Server!";
    char recvbuf[512];
    int iResult, recvbuflen = sizeof(recvbuf);

    WSAStartup(MAKEWORD(2,2), &wsaData);

    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    getaddrinfo("example.com", "80", &hints, &result);

    ConnectSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    connect(ConnectSocket, result->ai_addr, (int)result->ai_addrlen);

    iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);
    iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);

    closesocket(ConnectSocket);
    WSACleanup();
    return 0;
}