ws-overlappedwindow,cw-usedefault,cw-usedefault,
cw-usedefault,cw-usedefault,
null,null,hinstance,null);
if (!hwnd)
return (false);
showwindow(hwnd,ncmdshow);
updatewindow(hwnd);
/*给主窗口函数发送wm-user消息*/
postmessage(hwnd,wm-user,(wparam) 0,(lparam) 0);
while (getmessage(&msg,null,null,null)) {
translatemessage(&msg);
dispatchmessage(&msg);
}
return (msg.wparam);
}
主窗口函数clientproc是程序的主要部分,它处理相关的消息:在接到消息wm-user后,它调用函数wsastartup()初始化windows sockets dll,并检查其版本号,然后通过主机名获取主机地址;在接到消息wm-command时,如果是命令idm-start,则调用子程序client()建立套接字,并试图和服务器建立连接,如果是命令idm-stop,则调用函数wsacleanup()终止windows sockets dll,并发出终止应用程序的消息;在接到消息um-sock时,它根据参数lparam指示的网络事件,进行相应的操作,然后选择下一个期望的网络事件。
程序3:部分windows程序源代码(主窗口函数)
long far pascal
clientproc(hwnd hwnd, unsigned message, uint wparam, long lparam)
{
int length,i;
wsadatawsadata;/*描述windows sockets实现细节的数据结构*/
intstatus;
switch (message) {
case wm-user:
status=wsastartup(0x101,&wsadata);
if (status !=0) {
alertuser(hwnd,"wsastartup() failed");
postquitmessage(0);
}
if (lobyte(wsadata.wversion) !=1 || hibyte(wsadata.wversion) !=1)
{ /*现在支持的版本是winsock.dll 1.1*/
alertuser(hwnd, "wsastartup() version not match");
wsacleanup();
postquitmessage(0);
}
hostaddr=gethostbyname(server-address);
if (hostaddr==null) {
alertuser(hwnd, "gethostbyname error ");
wsacleanup ();
postquitmessage(0);
}
memcpy(&hostnm,hostaddr,sizeof(struct hostent));
break;
case wm-command:
switch (wparam) {
case idm-start:
if (!client(hwnd)) {
closesocket(s);
alertuser(hwnd, "start failed");
}
break;
case idm-stop:
wsacleanup();
postquitmessage(0);
break;
}
break;
case um-sock:
switch (lparam) {
case fd-connect:/*网络事件:连接建立*/
if (!set-select(hwnd, fd-write))/*选择:期望发送*/
closesocket(s);
break;
case fd-read:/*网络事件:读准备好*/
if (!receive-pkt(hwnd)) {/*接收数据*/
alertuser(hwnd, "receive packet failed");
closesocket(s);
break;
}
if (!set-select(hwnd, fd-write))/*选择:期望发送*/
closesocket(s);
break;
case fd-write:/*网络事件:写准备好*/
for (i=0;i<1024;i++)
buffer=(char) 'a'+i % 26;
length=1024;
if (!(send-pkt(hwnd,length))) {/*发送数据*/
alertuser(hwnd, "packet send failed");
closesocket(s);
break;
}
if (!set-select(hwnd, fd-read)) /*选择:期望接收*/
closesocket(s);
break;
case fd-close:/*网络事件:连接关闭。操作:停止异步选择*/
if (wsaasyncselect(s,hwnd,0,0)==socket-error)
alertuser(hwnd, "wsaasyncselect failed");
alertuser(hwnd, "socket has been closed");
break;
default:/*网络出错则警告,其他事件忽略*/
if (wsagetselecterror(1param) !=0) {
alertuser(hwnd, "socket report failure");
closesocket(s);
break;
}
break;
}
break;
case wm-destroy:
closesocket(s);/*关闭窗口前应该关闭套接字,并*/
wsacleanup();/*终止windows sockets dll*/
postquitmessage(0);
break;
default:
return (defwindowproc(hwnd, message,
wparam, lparam));
}
return (null);
}
程序4:部分windows程序源代码(子程序)
bool client(hwnd hwnd)/*客户机子程序*/
{
if (!make-skt(hwnd))/*建立套接字*/
return(false);
if (!set-select(hwnd,fd-connect))/*设置异步连接*/
return(false);
if (!connect-skt(hwnd))/*建立连接*/
return(false);
return(true);
}
bool receive-pkt(hwnd hwnd)/*接收数据子程序*/
{
hdc dc;
intlength;
int11,12,13;
charlinel,line2,line3;
count ++;/*循环计数器加1*/
if ((length=recv(s,lpbuffer,1024,0))==socket-error)
return(false); /*如果接收数据出错,则返回false*/
if (length==0) /*接收数据长度为零,表示连接中断*/
return(false);
if (dc=getdc(hwnd)) { /*接收数据成功,显示信息*/
11=wsprintf((lpstr) line1,"tcp echo client no.%d",count);
12=wsprintf((lpstr) line2,"received %d bytes", length);
13=wsprintf((lpstr) line3,"those are:%c,%c,%c,%c,%c,%c",
buffer,buffer,buffer,buffer,buffer,buffer
);
textout(dc, 10, 2, (lpstr) linel, 11);
textout(dc, 10, 22, (lpstr) line2, 12);
textout(dc, 10, 42, (lpstr) line3, 13);
releasedc(hwnd, dc);
}
return(true);
}
bool set-select(hwnd hwnd, long levent)/*异步选择子程序*/
{
if (wsaasyncselect(s,hwnd, um-sock, levent)==socket-error) {
alertuser(hwnd, "wsaasyncselect failed");
return (false);
}
return (true);
}
bool make-skt(hwnd hwnd)/*建立套接字子程序*/
{
if ((s=socket(af-inet,sock-type,0))==invalid-socket) {
alertuser(hwnd, "socket failed");
return (false);
}
return (true);
}
bool connect-skt(hwnd hwnd)/*建立连接子程序*/
{
memset((void*) &dst-addr, sizeof(dst-addr),0);
dst-addr.sin-family=af-inet;
dst-addr.sin-port=htons(userport);
dst-addr.sin-addr.s-addr=*((unsigned long *)hostnm.h-addr-list );
if (connect(s, (struct sockaddr *) & dst-addr,
sizeof(dst-addr))==socket-error) {
alertuser(hwnd, "connect failed");
return (false);
}
return (true);
}
bool send-pkt(hwnd hwnd, int len)/*发送数据子程序*/
{
int length;
if ((length=send(s,lpbuffer,len,0))==socket-error)
return (false);
else if (length !=len) {
alertuser(hwnd, "send length not match!");
return(false);
}
return (true);
}
我们用最简单的语句编制一个unix下基于bsd socket的服务器程序,它在建立连接后,只负责将收到的数据发回去,在连接断开后,服务器关闭套接字返回。要编制在windows下的服务器程序,可参照客户机程序,使用winsock的异步选择机制。
程序5:unix下服务器程序源代码
/*tcp/ip必要的头文件*/
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define userport 3333/*用户定义端口号,与客户机相同*/
#define host-ip-addr "166.111.8.80"/*我们的主机地址*/
main(int argc, char **argv)
{
char buf;/*buffer for sending and receiving data*/
struct sockaddr-in client;/*client address information*/
struct sockaddr-in server;/*server address information*/
int s;/*socket for accepting connections*/
int ns;/*socket connected to client*/
int namelen;/*length of client name*/
int pktlen;/*length of packet received or sended*/
if ((s = socket(af-inet,sock-stream, 0))<0) {
perror("socket()");
return;
}
/*bind the socket to the server address.*/
bzero((char*)&server, sizeof(server));
server.sin-len =sizeof(struct sockaddr-in);
server.sin-family=af-inet;
server.sin-port =htons(userport);
server.sin-addr.s-addr=inaddr-any;
if (bind(s, (struct sockaddr *)&server, sizeof(server)) <0) {
perror ("bind()");
return;
}
/*listen for connections. specify the backlog as 1. */
if (
