소켓 프로그래밍

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")




#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"


int __cdecl main(int argc, char** argv)
{
	WSADATA wsaData;
	SOCKET ConnectSocket = INVALID_SOCKET;
	struct addrinfo* result = NULL,
		* ptr = NULL,
		hints;
	const char* sendbuf = "this is a test";
	char recvbuf[DEFAULT_BUFLEN];
	int iResult;
	int recvbuflen = DEFAULT_BUFLEN;


	// Validate the parameters
	/*if (argc != 2) {
		printf("usage: %s server-name\n", argv[0]);
		return 1;
	}*/


	// Initialize Winsock
	iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (iResult != 0) {
		printf("WSAStartup failed with error: %d\n", iResult);
		return 1;
	}


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


	// Resolve the server address and port
	iResult = getaddrinfo("localhost", DEFAULT_PORT, &hints, &result);
	if (iResult != 0) {
		printf("getaddrinfo failed with error: %d\n", iResult);
		WSACleanup();
		return 1;
	}


	// Attempt to connect to an address until one succeeds
	for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {


		// Create a SOCKET for connecting to server
		ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
			ptr->ai_protocol);
		if (ConnectSocket == INVALID_SOCKET) {
			printf("socket failed with error: %ld\n", WSAGetLastError());
			WSACleanup();
			return 1;
		}


		// Connect to server.
		iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
		if (iResult == SOCKET_ERROR) {
			closesocket(ConnectSocket);
			ConnectSocket = INVALID_SOCKET;
			continue;
		}
		break;
	}


	freeaddrinfo(result);


	if (ConnectSocket == INVALID_SOCKET) {
		printf("Unable to connect to server!\n");
		WSACleanup();
		return 1;
	}


	// Send an initial buffer
	iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);
	if (iResult == SOCKET_ERROR) {
		printf("send failed with error: %d\n", WSAGetLastError());
		closesocket(ConnectSocket);
		WSACleanup();
		return 1;
	}


	printf("Bytes Sent: %ld\n", iResult);


	// shutdown the connection since no more data will be sent
	iResult = shutdown(ConnectSocket, SD_SEND);
	if (iResult == SOCKET_ERROR) {
		printf("shutdown failed with error: %d\n", WSAGetLastError());
		closesocket(ConnectSocket);
		WSACleanup();
		return 1;
	}


	// Receive until the peer closes the connection
	do {


		iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
		if (iResult > 0)
			printf("Bytes received: %d\n", iResult);
		else if (iResult == 0)
			printf("Connection closed\n");
		else
			printf("recv failed with error: %d\n", WSAGetLastError());


	} while (iResult > 0);


	// cleanup
	closesocket(ConnectSocket);
	WSACleanup();


	return 0;
}