echo_stream_server_winsock2.c

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) {
		fprintf(stderr, "WSAStartup failed.\n");
		exit(1);
	}

	int socketfd = socket(AF_INET, SOCK_STREAM, 0);
	if (socketfd == -1) {
		fprintf(stderr, "socket failed!\n");
		exit(1);
	}

	struct sockaddr_in sa;
	sa.sin_family = AF_INET;
	inet_pton(AF_INET, "0.0.0.0", &(sa.sin_addr));
	sa.sin_port = htons(12345);

	int ret = bind(socketfd, (const struct sockaddr*)&sa, sizeof(sa));
	if (ret == -1) {
		fprintf(stderr, "bind failed!\n");
		exit(1);
	}

	ret = listen(socketfd, 0);
	if (ret == -1) {
		fprintf(stderr, "listen failed!\n");
		exit(1);
	}

	struct sockaddr_in their_addr;
	socklen_t sin_size = sizeof(their_addr);
	int client_sock = accept(socketfd, (struct sockaddr *)&their_addr, &sin_size);
	if (client_sock == -1) {
		fprintf(stderr, "accept failed!\n");
		exit(1);
	}

	char buff[256];
	int len;
	while ((len = recv(client_sock, buff, sizeof(buff), 0)) != -1) {
		send(client_sock, "I received: ", strlen("I received: "), 0);
		send(client_sock, buff, len, 0);
	}
}