这篇文章主要介绍了c语言socket多线程编程,可以限制客户端连接数，大家参考使用吧
先上一些多线程需要使用的函数定义：
代码如下:
DWORD WINAPI ProcessClientRequests(LPVOID lpParam)//新线程将会执行的函数定义
{
return 0;
}
HANDLE handler=CreateThread(NULL, 0, ProcessClientRequests, &clientsocket, 0, NULL);//这里比较简单，&clientsocket是个指针，是从主线程传入新线程的参数
WaitForMultipleObjects(MAXCLIENTS, threads, TRUE, INFINITE);//用来阻塞主线程，直到所有创建的子线程都完成任务为止，才继续执行后面的代码
for(int i=0;i<MAXCLIENTS; i++)
{
CloseHandle(threads[i]);//创建的每个子线程的HANDLE都会被保存在HANDLE数组中，这个函数用于关闭各个handle所对应的线程空间
}
服务器端程序
主线程代码如下：
代码如下:
#define MAXCLIENTS 3//宏定义，最多3个客户端连接
int main()
{
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
HANDLE threads[MAXCLIENTS];
SOCKET s=socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
sockaddr_in sockaddr;
sockaddr.sin_family=PF_INET;
sockaddr.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");
sockaddr.sin_port=htons(9000);
bind(s, (SOCKADDR*)&sockaddr, sizeof(SOCKADDR));
listen(s, 1);
printf("listening on port [%d].n", 9000);
int existingClientCount=0;
while(TRUE)
{
SOCKADDR clientAddr;
int size=sizeof(SOCKADDR);
SOCKET clientsocket;
clientsocket=accept(s, &clientAddr, &size);
printf("***SYS***New client touched.n");
if(existingClientCount<MAXCLIENTS)//判断是否已经超出最大连接数了
{
threads[existingClientCount++]=CreateThread(NULL, 0, ProcessClientRequests, &clientsocket, 0, NULL);//启动新线程，并且将socket传入
}
else
{
char* msg="Exceeded Max incoming requests, will refused this connect!rn";
send(clientsocket, msg, strlen(msg)+sizeof(char), NULL);//发送拒绝连接消息给客户端
printf("***SYS***REFUSED.n");
closesocket(clientsocket);//释放资源
break;
}
}
printf("Maximize clients occurred for d%.rn", MAXCLIENTS);
WaitForMultipleObjects(MAXCLIENTS, threads, TRUE, INFINITE);//等待所有子线程，直到完成为止
closesocket(s);
for(int i=0;i<MAXCLIENTS; i++)
{
CloseHandle(threads[i]);//清理线程资源
}
WSACleanup();
printf("Cleared all.rn");
getchar();
exit(0);
}
子线程函数定义
代码如下:
DWORD WINAPI ProcessClientRequests(LPVOID lpParam)
{
SOCKET* clientsocket=(SOCKET*)lpParam;//这里需要强制转换，注意：指针类型的
char* msg="Hello, my client.rn";
send(*clientsocket, msg, strlen(msg)+sizeof(char), NULL);
printf("***SYS***HELLO.n");
while(TRUE)
{
char buffer[MAXBYTE]={0};
recv(*clientsocket, buffer, MAXBYTE, NULL);
if(strcmp(buffer, "exit")==0)
{
char* msg_bye="Bye.rn";
send(*clientsocket, msg_bye, strlen(msg_bye)+sizeof(char), NULL);
break;
}
printf("***Client***%sn", buffer);
}
closesocket(*clientsocket);
return 0;
}
