UDP编程
2008-03-08 12:27:08 来源:WEB开发网核心提示:一、说明 使用UDP时,直接使用API代替控件,UDP编程, 第一个程序(ReadBufferUdp)使用来接收到缓存中, "Destino"变量非常重要,(gvEncerrar被设置为全局变量,) 超时时间设置,假如你从其他地方接收数据到Buffer,你必须设置Destino = 0 并且在以
一、说明
使用UDP时,直接使用API代替控件。 第一个程序(ReadBufferUdp)使用来接收到缓存中。 "Destino"变量非常重要,假如你从其他地方接收数据到Buffer,你必须设置Destino = 0 并且在以后执行的时候赋值你将要发送的包的地址给它(after the execution it will have the address which send you the packet.)。
假如你只想从一个指定的地址接收数据,你必须设置变量Destino = <address>. "gvEncerrar" 用来中止处理过程。(gvEncerrar被设置为全局变量。) 超时时间设置。"Inicio + 12" = 12 sec of timeout.
第三个程序是用来预备WinSock程序。 二、代码 int ReadBufferUdp(unsigned long *Destino,void *T,int Size)
{
char Buffer[128];
SOCKADDR_IN SockAddr;
int LenSockAddr=sizeof(SOCKADDR_IN);
fd_set FdRead;
strUCt timeval t_val;
int Ret;
time_t Inicio = time(NULL); application->PRocessMessages();
if(gvEncerrar)
return false; FD_ZERO(&FdRead);
FD_SET(gvSocket,&FdRead);
t_val.tv_sec=0;
t_val.tv_usec=0; while((Ret=select(0,&FdRead,NULL,NULL,&t_val))!=1 && (Inicio + 12) >
time(NULL) && !gvEncerrar)
{
FD_ZERO(&FdRead);
FD_SET(gvSocket,&FdRead);
t_val.tv_sec=0;
t_val.tv_usec=0;
Application->ProcessMessages();
}
if(Ret != 1)
return false; if(recvfrom(gvSocket,Buffer,Size,0,(LPSOCKADDR)&SockAddr,&LenSockAddr)!=Size) return false; if(*Destino == 0)
{
*Destino = SockAddr.sin_addr.s_addr;
}
else
if(*Destino != SockAddr.sin_addr.s_addr)
return false; memcpy(T,Buffer,Size);
return true;
} int WriteBufferUdp(unsigned long Destino,void *T,int Size)
{
SOCKADDR_IN SockAddr;
int Sent; Application->ProcessMessages();
SockAddr.sin_family = AF_INET;
SockAddr.sin_port = gvPortUdp;
SockAddr.sin_addr.s_addr = Destino;
Sent = sendto(gvSocket,(char
*)T,Size,0,(LPSOCKADDR)&SockAddr,sizeof(SockAddr));
if(Sent != Size)
return false;
else
return true;
} void InicializaTCPip()
{ Word wVersionRequested;
WSADATA wsaData;
IN_ADDR In;
PSERVENT PServent;
SOCKADDR_IN SockAddrIn;
wVersionRequested = MAKEWORD( 1, 1 );
if(WSAStartup( wVersionRequested, &wsaData ))
{
ShowMessage("Erro na inicializao do TCP/IP");
Application->Terminate();
return;
} // Get the port on service file
if((PServent=getservbyname("your_service_name","udp"))==NULL)
{
ShowMessage("Erro oBTendo port do servi transurb/udp");
Application->Terminate();
return;
}
gvPortUdp = PServent->s_port;
sprintf(StrAux,"Servi transurb/udp port:%d",ntohs(gvPortUdp));
Log(StrAux); // Open de Socket
if((gvSocket = socket(AF_INET,SOCK_DGRAM,0))==INVALID_SOCKET)
{
ShowMessage("Erro na criao do socket");
Application->Terminate();
return;
}
Log("Socket criado com sucesso"); // Do the bind
SockAddrIn.sin_family = AF_INET;
SockAddrIn.sin_port = gvPortUdp;
SockAddrIn.sin_addr.s_addr = NULL; if(bind(gvSocket,(LPSOCKADDR)&SockAddrIn,sizeof(SockAddrIn))==SOCKET_ERROR) {
ShowMessage("Erro no bind do socket");
Application->Terminate();
return;
}
Log("Bind do socket com sucesso"); }
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