Server socket program

socket It's a kind of IPC Method , This article implements a simple server routine , Used to understand socket Application framework .

socket Function to create a socket .
bind The function is used to allocate ip Address and port number .
listen Function to turn the socket into a connection ready state .
accept Function accepts the connection request . If you call this function without a connection , Will not return , Until there is a connection request .
connect Function to send a connection request to the server .
windows End writing socket, Need to call ws2_32.lib Kuhe WSAStartup function .

WSADATA ws;	// Initialize dynamic link library 
WSAStartup(MAKEWORD(2,2), &ws);// The main version is 2, The sub version is 2

Functions can be used in the linux The input man see , Or read related books .

#include <string.h>
#include <stdlib.h>
#ifdef WIN32//Windows Compile... In environment 
#include <Windows.h>
#else//linux Compile... In environment 
#include <sys/types.h> 
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#define closesocket close //linux Use in close function 
#endif

#include <stdio.h>
int main(int argc, char *argv[])
{
    
#ifdef WIN32
	WSADATA ws;	// Initialize dynamic link library 
	WSAStartup(MAKEWORD(2,2), &ws);// The main version is 2, The sub version is 2
#endif
	int sock = socket(AF_INET, SOCK_STREAM, 0);//TCP 
	if (sock == -1) {
    
		printf("create socket failed!\n");
		return -1;
	}
	unsigned short port = 8080;
	if (argc > 1) {
    
		port = atoi(argv[1]);// Convert a string to an integer 
	}
	sockaddr_in saddr;
	saddr.sin_family = AF_INET;
	saddr.sin_port = htons(port);// Note byte order conversion 
	saddr.sin_addr.s_addr = htonl(0);

	if (bind(sock, (sockaddr*)&saddr, sizeof(saddr)) != 0) {
    
		printf("bind port %d failed!\n", port);
		return -2;
	}
	printf("bind port %d success!\n", port);
	listen(sock, 10);

	sockaddr_in caddr;
	socklen_t len = sizeof(caddr);
	int client = accept(sock, (sockaddr*)&caddr, &len);
	printf("accept client %d\n", client);
	char *ip = inet_ntoa(caddr.sin_addr);
	unsigned short cport = ntohs(caddr.sin_port);
	printf("client ip is %s,port is %d\n", ip, cport);
	char buf[1024] = {
     0 };
	for (;;)
	{
    
		int recvlen = recv(client, buf, sizeof(buf) - 1, 0);
		if (recvlen <= 0) break;
		buf[recvlen] = '\0';
		if (strstr(buf, "quit") != NULL) {
    
			char re[] = "quit success!\n";
			send(client, re, strlen(re) + 1, 0);//strlen The obtained string size does not include \0
			break;
		} 
		send(client, "ok\n", 4, 0);
		printf("recv %s\n", buf);
	}
	closesocket(client);
	closesocket(sock);
	getchar();
	return 0;
}

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