c语言socket多线程编程限制客户端连接数
先上一些多线程需要使用的函数定义：
DWORDWINAPIProcessClientRequests(LPVOIDlpParam) //新线程将会执行的函数定义
{
return0;
}
HANDLEhandler=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(inti=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：
#defineMAXCLIENTS3 //宏定义，最多3个客户端连接
intmain()
{
WSADATAwsaData;
WSAStartup(MAKEWORD(2,2),&wsaData);
HANDLEthreads[MAXCLIENTS];
SOCKETs=socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
sockaddr_insockaddr;
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("listeningonport[%d].\n",9000);
intexistingClientCount=0;
while(TRUE)
{
SOCKADDRclientAddr;
intsize=sizeof(SOCKADDR);
SOCKETclientsocket;
clientsocket=accept(s,&clientAddr,&size);
printf("***SYS*** Newclienttouched.\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="ExceededMaxincomingrequests,willrefusedthisconnect!\r\n";
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("Maximizeclientsoccurredford%.\r\n",MAXCLIENTS);
WaitForMultipleObjects(MAXCLIENTS,threads,TRUE,INFINITE); //等待所有子线程，直到完成为止
closesocket(s);
for(inti=0;i<MAXCLIENTS;i++)
{
CloseHandle(threads[i]); //清理线程资源
}
WSACleanup();
printf("Clearedall.\r\n");
getchar();
exit(0);
}
子线程函数定义
char*msg="Hello,myclient.\r\n"; while(TRUE) return0;
DWORDWINAPIProcessClientRequests(LPVOIDlpParam)
{
SOCKET*clientsocket=(SOCKET*)lpParam; //这里需要强制转换，注意：指针类型的
send(*clientsocket,msg,strlen(msg)+sizeof(char),NULL);
printf("***SYS*** HELLO.\n");
{
charbuffer[MAXBYTE]={0};
recv(*clientsocket,buffer,MAXBYTE,NULL);
if(strcmp(buffer,"exit")==0)
{
char*msg_bye="Bye.\r\n";
send(*clientsocket,msg_bye,strlen(msg_bye)+sizeof(char),NULL);
break;
}
printf("***Client*** %s\n",buffer);
}
closesocket(*clientsocket);
}
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