tcp_non_block_apply3_server.cpp

#include <cstdio>
#include <winsock.h>

#define MaxClientNum 5

int main() {
	SOCKET sd, clnt_sd[MaxClientNum];
	WSADATA wsadata;
	struct sockaddr_in serv{}, clnt{};
	int n;
	int current_client_num;
	bool exit = false;
	char str[100] = "I love NP!";

	WSAStartup(0x101, &wsadata);
	sd = socket(AF_INET, SOCK_STREAM, 0);
	serv.sin_family = AF_INET;
	serv.sin_port = htons(1234);
	serv.sin_addr.s_addr = inet_addr("127.0.0.1");

	bind(sd, (struct sockaddr *) &serv, sizeof(serv));

	listen(sd, 5);

	//enable non-blocking mode when iMode=1
	u_long iMode = 1;
	ioctlsocket(sd, FIONBIO, &iMode);

	int clnt_len = sizeof(clnt);
	printf("Server waits.\n");

	for (int i = 0; i < MaxClientNum; i++) {
		clnt_sd[i] = -1;
	}

	current_client_num = 0;

	while (true) {
		n = accept(sd, (struct sockaddr *) &clnt, &clnt_len);
		if (n != -1) {
			clnt_sd[current_client_num] = n;
			printf("Client[%d] is connected.\n", current_client_num);
			current_client_num++;
		}


		for (int i = 0; i < MaxClientNum; i++) {
			if (clnt_sd[i] != -1) {
				send(clnt_sd[i], str, strlen(str) + 1, 0);
				printf("Send to clnt_sd[%d]: %s\n", i, str);

				if (strcmp(str, "exit") == 0) {
					exit = true;
					break;
				}
			}
		}

		if(exit) {
			break;
		}

		Sleep(1000);
	}

	closesocket(sd);

	for (unsigned i : clnt_sd) {
		closesocket(i);
	}

	WSACleanup();
	//system("pause");
}