用了別人寫得程式，但是沒搞懂。。。
用的select模型，是不是就是同步的方式，那阻塞和非阻塞有是怎么判斷的呢
Init里面就是連接和接收資料
TcpInit()
{
if (!m_bClientConnected)
{
int m_nPortRemote = 5025;
CString m_strRemoteIP = _T("192.168.1.58");
DWORD IP = inet_addr((LPCTSTR)m_strRemoteIP);
if(!m_pSockClient->Connect(m_strRemoteIP,m_nPortRemote))
{
int a=0;
return;
}
if(!m_pSockClient->StartReceiving(TcpStatusChangeCallBack,TcpRecvCallBack,(DWORD)this))
{
int a=0;
m_pSockClient->Close();
return;
}
m_bClientConnected=TRUE;
}
WriteCmd("FORMat:DATA INT,16\n",20);
}
接收資料里面開啟了一個執行緒，并且有兩個回呼函式，一個狀態一個資料
StartReceiving(LPStatusProc proc1,LPDataArriveProc proc2,DWORD userdata)
{
if(!m_bAvailable)
{
return FALSE;
}
if(m_nType==TCP_SOCKET_SERVER)
{
return FALSE;
}
if(!m_bCreated)
{
return FALSE;
}
if(m_bAuto)
{
return FALSE;
}
//開始自動接收
m_lpClientStatusProc=proc1;
m_lpClientDataArriveProc=proc2;
m_dwUserData=https://bbs.csdn.net/topics/userdata;
m_bAuto=TRUE;
DWORD dwThreadId;
m_hServerThread=CreateThread(NULL,0,ClientThread,this,0,&dwThreadId);
if(m_hServerThread==NULL)
{
m_bAuto=FALSE;
error=WSAGetLastError();
return FALSE;
}
return TRUE;
}
客戶端執行緒
ClientThread(LPVOID lpParameter)
{
CTCPSocket* m_pTCP=(CTCPSocket*)lpParameter;
int nRet;
char buf[256];
timeval tv={0,5000};
fd_set fs;
//不斷接收服務器發來資料
while(m_pTCP->m_bAuto)
{
FD_ZERO(&fs);
FD_SET(m_pTCP->m_sSocket,&fs);
if(select(1,&fs,NULL,NULL,&tv)==1)
{
nRet=recv(m_pTCP->m_sSocket,buf,256,0);
if(nRet==SOCKET_ERROR)
{
//出錯斷開(例如服務器關閉)
m_pTCP->error=WSAGetLastError();
closesocket(m_pTCP->m_sSocket);
m_pTCP->m_bAuto=FALSE;
TRACE("客戶端出錯斷開! \n");
//回呼處理
if(m_pTCP->m_lpClientStatusProc!=NULL)
{
char* inf;
inf=new char[22];
inf[0]='C';
inf[1]='D';
m_pTCP->m_lpClientStatusProc(inf,22,m_pTCP->m_dwUserData);
delete inf;
}
break;
}
if(nRet>0)
{
//收到新的資料
//TRACE("客戶端收到資料%d位元組! \n",nRet);
//資料回呼處理
if(m_pTCP->m_lpClientDataArriveProc!=NULL)
{
char* inf;
inf=new char[nRet];
memcpy(inf,buf,nRet);
m_pTCP->m_lpClientDataArriveProc(inf,nRet,m_pTCP->m_dwUserData);
delete inf;
}
continue;
}
if(nRet==0)
{
//服務器正常斷開
TRACE("客戶端正常斷開! \n");
//回呼處理
if(m_pTCP->m_lpClientStatusProc!=NULL)
{
char* inf;
inf=new char[22];
inf[0]='C';
inf[1]='D';
m_pTCP->m_lpClientStatusProc(inf,22,m_pTCP->m_dwUserData);
delete inf;
}
closesocket(m_pTCP->m_sSocket);
m_pTCP->m_bAuto=FALSE;
break;
}
}
}
return 0;
}
uj5u.com熱心網友回復：
感覺是同步阻塞的方式？能不能改成非阻塞呢uj5u.com熱心網友回復：
僅供參考：MSDN98_1\SAMPLES\VC98\SDK\NETDS\WINSOCK\SIMPLE\SIMPLEC.C
/******************************************************************************\
* simplec.c - Simple TCP/UDP client using Winsock 1.1
*
* This is a part of the Microsoft Source Code Samples.
* Copyright 1996-1997 Microsoft Corporation.
* All rights reserved.
* This source code is only intended as a supplement to
* Microsoft Development Tools and/or WinHelp documentation.
* See these sources for detailed information regarding the
* Microsoft samples programs.
\******************************************************************************/
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define DEFAULT_PORT 5001
#define DEFAULT_PROTO SOCK_STREAM // TCP
void Usage(char *progname) {
fprintf(stderr,"Usage\n%s -p [protocol] -n [server] -e [endpoint] \
-l [iterations]\n",
progname);
fprintf(stderr,"Where:\n\tprotocol is one of TCP or UDP\n");
fprintf(stderr,"\tserver is the IP address or name of server\n");
fprintf(stderr,"\tendpoint is the port to listen on\n");
fprintf(stderr,"\titerations is the number of loops to execute\n");
fprintf(stderr,"\t(-l by itself makes client run in an infinite loop,");
fprintf(stderr," Hit Ctrl-C to terminate it)\n");
fprintf(stderr,"Defaults are TCP , localhost and 5001\n");
WSACleanup();
exit(1);
}
int main(int argc, char **argv) {
char Buffer[128];
char *server_name= "localhost";
unsigned short port = DEFAULT_PORT;
int retval, loopflag=0;
int i, loopcount,maxloop=-1;
unsigned int addr;
int socket_type = DEFAULT_PROTO;
struct sockaddr_in server;
struct hostent *hp;
WSADATA wsaData;
SOCKET conn_socket;
if (argc >1) {
for(i=1;i <argc;i++) {
if ( (argv[i][0] == '-') || (argv[i][0] == '/') ) {
switch(tolower(argv[i][1])) {
case 'p':
if (!stricmp(argv[i+1], "TCP") )
socket_type = SOCK_STREAM;
else if (!stricmp(argv[i+1], "UDP") )
socket_type = SOCK_DGRAM;
else
Usage(argv[0]);
i++;
break;
case 'n':
server_name = argv[++i];
break;
case 'e':
port = atoi(argv[++i]);
break;
case 'l':
loopflag =1;
if (argv[i+1]) {
if (argv[i+1][0] != '-')
maxloop = atoi(argv[i+1]);
}
else
maxloop = -1;
i++;
break;
default:
Usage(argv[0]);
break;
}
}
else
Usage(argv[0]);
}
}
if (WSAStartup(0x202,&wsaData) == SOCKET_ERROR) {
fprintf(stderr,"WSAStartup failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
if (port == 0){
Usage(argv[0]);
}
//
// Attempt to detect if we should call gethostbyname() or
// gethostbyaddr()
if (isalpha(server_name[0])) { /* server address is a name */
hp = gethostbyname(server_name);
}
else { /* Convert nnn.nnn address to a usable one */
addr = inet_addr(server_name);
hp = gethostbyaddr((char *)&addr,4,AF_INET);
}
if (hp == NULL ) {
fprintf(stderr,"Client: Cannot resolve address [%s]: Error %d\n",
server_name,WSAGetLastError());
WSACleanup();
exit(1);
}
//
// Copy the resolved information into the sockaddr_in structure
//
memset(&server,0,sizeof(server));
memcpy(&(server.sin_addr),hp->h_addr,hp->h_length);
server.sin_family = hp->h_addrtype;
server.sin_port = htons(port);
conn_socket = socket(AF_INET,socket_type,0); /* Open a socket */
if (conn_socket <0 ) {
fprintf(stderr,"Client: Error Opening socket: Error %d\n",
WSAGetLastError());
WSACleanup();
return -1;
}
//
// Notice that nothing in this code is specific to whether we
// are using UDP or TCP.
// We achieve this by using a simple trick.
// When connect() is called on a datagram socket, it does not
// actually establish the connection as a stream (TCP) socket
// would. Instead, TCP/IP establishes the remote half of the
// ( LocalIPAddress, LocalPort, RemoteIP, RemotePort) mapping.
// This enables us to use send() and recv() on datagram sockets,
// instead of recvfrom() and sendto()
printf("Client connecting to: %s\n",hp->h_name);
if (connect(conn_socket,(struct sockaddr*)&server,sizeof(server))
== SOCKET_ERROR) {
fprintf(stderr,"connect() failed: %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
// cook up a string to send
//
loopcount =0;
while(1) {
wsprintf(Buffer,"This is a small test message [number %d]",loopcount++);
retval = send(conn_socket,Buffer,sizeof(Buffer),0);
if (retval == SOCKET_ERROR) {
fprintf(stderr,"send() failed: error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
printf("Sent Data [%s]\n",Buffer);
retval = recv(conn_socket,Buffer,sizeof (Buffer),0 );
if (retval == SOCKET_ERROR) {
fprintf(stderr,"recv() failed: error %d\n",WSAGetLastError());
closesocket(conn_socket);
WSACleanup();
return -1;
}
//
// We are not likely to see this with UDP, since there is no
// 'connection' established.
//
if (retval == 0) {
printf("Server closed connection\n");
closesocket(conn_socket);
WSACleanup();
return -1;
}
printf("Received %d bytes, data [%s] from server\n",retval,Buffer);
if (!loopflag){
printf("Terminating connection\n");
break;
}
else {
if ( (loopcount >= maxloop) && (maxloop >0) )
break;
}
}
closesocket(conn_socket);
WSACleanup();
}
uj5u.com熱心網友回復：
MSDN98_1\SAMPLES\VC98\SDK\NETDS\WINSOCK\SIMPLE\SIMPLES.C/******************************************************************************\
* simples.c - Simple TCP/UDP server using Winsock 1.1
* This is a part of the Microsoft Source Code Samples.
* Copyright 1996-1997 Microsoft Corporation.
* All rights reserved.
* This source code is only intended as a supplement to
* Microsoft Development Tools and/or WinHelp documentation.
* See these sources for detailed information regarding the
* Microsoft samples programs.
\******************************************************************************/
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define DEFAULT_PORT 5001
#define DEFAULT_PROTO SOCK_STREAM // TCP
void Usage(char *progname) {
fprintf(stderr,"Usage\n%s -p [protocol] -e [endpoint] -i [interface]\n",
progname);
fprintf(stderr,"Where:\n\tprotocol is one of TCP or UDP\n");
fprintf(stderr,"\tendpoint is the port to listen on\n");
fprintf(stderr,"\tinterface is the ipaddr (in dotted decimal notation)");
fprintf(stderr," to bind to\n");
fprintf(stderr,"Defaults are TCP,5001 and INADDR_ANY\n");
WSACleanup();
exit(1);
}
int main(int argc, char **argv) {
char Buffer[128];
char *interface= NULL;
unsigned short port=DEFAULT_PORT;
int retval;
int fromlen;
int i;
int socket_type = DEFAULT_PROTO;
struct sockaddr_in local, from;
WSADATA wsaData;
SOCKET listen_socket, msgsock;
/* Parse arguments */
if (argc >1) {
for(i=1;i <argc;i++) {
if ( (argv[i][0] == '-') || (argv[i][0] == '/') ) {
switch(tolower(argv[i][1])) {
case 'p':
if (!stricmp(argv[i+1], "TCP") )
socket_type = SOCK_STREAM;
else if (!stricmp(argv[i+1], "UDP") )
socket_type = SOCK_DGRAM;
else
Usage(argv[0]);
i++;
break;
case 'i':
interface = argv[++i];
break;
case 'e':
port = atoi(argv[++i]);
break;
default:
Usage(argv[0]);
break;
}
}
else
Usage(argv[0]);
}
}
if (WSAStartup(0x202,&wsaData) == SOCKET_ERROR) {
fprintf(stderr,"WSAStartup failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
if (port == 0){
Usage(argv[0]);
}
local.sin_family = AF_INET;
local.sin_addr.s_addr = (!interface)?INADDR_ANY:inet_addr(interface);
/*
* Port MUST be in Network Byte Order
*/
local.sin_port = htons(port);
listen_socket = socket(AF_INET, socket_type,0); // TCP socket
if (listen_socket == INVALID_SOCKET){
fprintf(stderr,"socket() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
//
// bind() associates a local address and port combination with the
// socket just created. This is most useful when the application is a
// server that has a well-known port that clients know about in advance.
//
if (bind(listen_socket,(struct sockaddr*)&local,sizeof(local) )
== SOCKET_ERROR) {
fprintf(stderr,"bind() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
//
// So far, everything we did was applicable to TCP as well as UDP.
// However, there are certain steps that do not work when the server is
// using UDP.
//
// We cannot listen() on a UDP socket.
if (socket_type != SOCK_DGRAM) {
if (listen(listen_socket,5) == SOCKET_ERROR) {
fprintf(stderr,"listen() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
}
printf("%s: 'Listening' on port %d, protocol %s\n",argv[0],port,
(socket_type == SOCK_STREAM)?"TCP":"UDP");
while(1) {
fromlen =sizeof(from);
//
// accept() doesn't make sense on UDP, since we do not listen()
//
if (socket_type != SOCK_DGRAM) {
msgsock = accept(listen_socket,(struct sockaddr*)&from, &fromlen);
if (msgsock == INVALID_SOCKET) {
fprintf(stderr,"accept() error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
printf("accepted connection from %s, port %d\n",
inet_ntoa(from.sin_addr),
htons(from.sin_port)) ;
}
else
msgsock = listen_socket;
//
// In the case of SOCK_STREAM, the server can do recv() and
// send() on the accepted socket and then close it.
// However, for SOCK_DGRAM (UDP), the server will do
// recvfrom() and sendto() in a loop.
if (socket_type != SOCK_DGRAM)
retval = recv(msgsock,Buffer,sizeof (Buffer),0 );
else {
retval = recvfrom(msgsock,Buffer,sizeof (Buffer),0,
(struct sockaddr *)&from,&fromlen);
printf("Received datagram from %s\n",inet_ntoa(from.sin_addr));
}
if (retval == SOCKET_ERROR) {
fprintf(stderr,"recv() failed: error %d\n",WSAGetLastError());
closesocket(msgsock);
continue;
}
if (retval == 0) {
printf("Client closed connection\n");
closesocket(msgsock);
continue;
}
printf("Received %d bytes, data [%s] from client\n",retval,Buffer);
printf("Echoing same data back to client\n");
if (socket_type != SOCK_DGRAM)
retval = send(msgsock,Buffer,sizeof(Buffer),0);
else
retval = sendto(msgsock,Buffer,sizeof (Buffer),0,
(struct sockaddr *)&from,fromlen);
if (retval == SOCKET_ERROR) {
fprintf(stderr,"send() failed: error %d\n",WSAGetLastError());
}
if (socket_type != SOCK_DGRAM){
printf("Terminating connection\n");
closesocket(msgsock);
}
else
printf("UDP server looping back for more requests\n");
continue;
}
}
uj5u.com熱心網友回復：
MSDN98_1\SAMPLES\VC98\SDK\NETDS\WINSOCK\SIMPLE\IOCTL.C/******************************************************************************\
* ioctl.c - TCP server
*
* This is a part of the Microsoft Source Code Samples.
* Copyright 1996-1997 Microsoft Corporation.
* All rights reserved.
* This source code is only intended as a supplement to
* Microsoft Development Tools and/or WinHelp documentation.
* See these sources for detailed information regarding the
* Microsoft samples programs.
\******************************************************************************/
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define DEFAULT_PORT 5001
int ReadAndEcho(SOCKET , char *,int ) ;
int WriteMessage(SOCKET , char *,int ) ;
void Usage(char *progname) {
fprintf(stderr,"Usage\n%s -e [endpoint] -i [interface]\n",
progname);
fprintf(stderr,"Where:\n");
fprintf(stderr,"\tendpoint is the port to listen on\n");
fprintf(stderr,"\tinterface is the ipaddr (in dotted decimal notation)");
fprintf(stderr," to bind to\n");
fprintf(stderr,"Defaults are 5001 and INADDR_ANY\n");
WSACleanup();
exit(1);
}
int main(int argc, char **argv) {
char Buffer[128];
char *interface= NULL;
unsigned short port=DEFAULT_PORT;
int fromlen;
int i, ioctl_opt =1;
struct sockaddr_in local, from;
WSADATA wsaData;
SOCKET listen_socket, msgsock;
fd_set readfds, writefds, exceptfds;
/* Parse arguments */
if (argc >1) {
for(i=1;i <argc;i++) {
if ( (argv[i][0] == '-') || (argv[i][0] == '/') ) {
switch(tolower(argv[i][1])) {
case 'i':
interface = argv[++i];
break;
case 'e':
port = atoi(argv[++i]);
break;
default:
Usage(argv[0]);
break;
}
}
else
Usage(argv[0]);
}
}
if (WSAStartup(0x202,&wsaData) == SOCKET_ERROR) {
fprintf(stderr,"WSAStartup failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
if (port == 0){
Usage(argv[0]);
}
//
// The fd sets should be zeroed out before using them to prevent errors.
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&exceptfds);
memset(Buffer,0,sizeof(Buffer));
local.sin_family = AF_INET;
//
// bind to specific interface if desired.
local.sin_addr.s_addr = (!interface)?INADDR_ANY:inet_addr(interface);
/*
* Port MUST be in Network Byte Order
*/
local.sin_port = htons(port);
listen_socket = socket(AF_INET, SOCK_STREAM,0); // TCP socket
if (listen_socket == INVALID_SOCKET){
fprintf(stderr,"socket() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
//
// bind() associates a local address and port combination with the
// socket just created.
if (bind(listen_socket,(struct sockaddr*)&local,sizeof(local) )
== SOCKET_ERROR) {
fprintf(stderr,"bind() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
//
// start listening on the socket for incoming connections
//
if (listen(listen_socket,5) == SOCKET_ERROR) {
fprintf(stderr,"listen() failed with error %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
printf("%s: Listening on port %d\n",argv[0],port);
//
// Set the socket to non-blocking mode.
//
if (ioctlsocket(listen_socket,FIONBIO,&ioctl_opt) == SOCKET_ERROR) {
fprintf(stderr,"ioctlsocket failed %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
//
// The structure of the loop below is very simple. We only accept one
// connection at a time. As soon as another client connects, we
// disconnect the first one, and start talking to the new client.
// All this server does is to echo the data received on the socket
// back to the client.
//
// This is not a very realistic server, but it does serve to show that
// select() does not scale very well on win32. If we were dealing
// with more than one client, we would have to have a list of sockets
// that are in each fdset to be able to check them when select()
// returns.
//
while(1) {
//
// A socket in the listen() state becomes ready to read when a
// client connects to it. An accept() will complete without
// blocking.
// Since select sets the sockets that are ready to be read from or
// written to, we have to include listen_socket in the fdset each time
// through the loop.
//
FD_SET(listen_socket,&readfds);
i = select(0,&readfds,&writefds,&exceptfds,NULL);
if (i == SOCKET_ERROR) {
fprintf(stderr,"select failed %d\n",WSAGetLastError());
}
if (i==0){
fprintf(stderr,"Select returned no fds ready\n");
}
if (FD_ISSET(listen_socket, &readfds)){
//
// close the previous client socket.
// We must also clear it from the fdset to prevent select()
// from failing.
//
closesocket(msgsock);
FD_CLR(msgsock,&readfds);
FD_CLR(msgsock,&writefds);
fromlen = sizeof(from);
msgsock= accept(listen_socket,(struct sockaddr*)&from,&fromlen);
if (msgsock == INVALID_SOCKET) {
fprintf(stderr,"accept failed %d\n",WSAGetLastError());
WSACleanup();
return -1;
}
FD_SET(msgsock,&writefds);
FD_SET(msgsock,&readfds);
continue;
}
if (FD_ISSET(msgsock,&readfds) ) {
//
// socket is ready to read, i.e., there is data on the socket.
//
if (ReadAndEcho(msgsock,Buffer,sizeof(Buffer))<0) {
fprintf(stderr,"terminating connection\n");
FD_CLR(msgsock,&readfds);
FD_CLR(msgsock,&writefds);
closesocket(msgsock);
continue;
}
}
if (FD_ISSET(msgsock,&writefds) ){
if (WriteMessage(msgsock,Buffer,sizeof(Buffer)) <=0) {
fprintf(stderr,"terminating connection\n");
FD_CLR(msgsock,&readfds);
FD_CLR(msgsock,&writefds);
closesocket(msgsock);
continue;
}
}
FD_SET(msgsock,&writefds);
FD_SET(msgsock,&readfds);
}
}
int ReadAndEcho(SOCKET insock, char *Buffer,int size) {
int rc;
rc = recv(insock,Buffer,size,0);
if (rc == SOCKET_ERROR) {
fprintf(stderr,"recv() failed with error %d\n",WSAGetLastError());
return -1;
}
if (rc ==0) {
fprintf(stderr,"Connection closed by client\n");
return 0;
}
printf("Received [%s] from client\n",Buffer);
return rc;
}
int WriteMessage(SOCKET outsock, char *Buffer,int size) {
int rc;
int lasterr;
printf("Sending [%s] to client\n",Buffer);
rc = send(outsock,Buffer,size, 0);
if (rc == SOCKET_ERROR) {
lasterr = WSAGetLastError();
if (lasterr == WSAEWOULDBLOCK)
return 0;
else {
fprintf(stderr,"send() failed with error %d\n",lasterr);
return -1;
}
}
if (rc ==0) {
fprintf(stderr,"Connection closed by client\n");
}
return rc;
}
uj5u.com熱心網友回復：
同步是阻塞的，異步是非阻塞的，所謂阻塞，就是你發送資料，然后等待回傳資料，資料沒有回傳，就死等，直到資料回傳或者超時；非阻塞是你發出一個接收命令，命令發出后不管資料有沒有收到，就執行代碼的后面的指令，而當資料回傳后，系統發出事件通知你處理接收到的資料，這種模式是非阻塞，是異步的
uj5u.com熱心網友回復：
是否阻塞, 是看socket有沒有設定非阻塞模式, 默認創建的socket都是阻塞模式,需要呼叫api ioctlsocket設定非阻塞模式.
select一般都是為了把非阻塞模式的, 變成阻塞模式. 為何這么做, 為什么不直接使用阻塞模式呢?
因為select可以同時判斷多個socket連接中是否有資料可以接收, 阻塞模式做不到.
并且同時也能做到沒有資料的時候,阻塞等待有資料才做事情, 不會浪費CPU. 有阻塞模式的相同的好處.
再并且, 還可方便的設定接收超時. 跟阻塞模式一樣.
uj5u.com熱心網友回復：
恩，那上面那個程式應該就是同步阻塞的？
uj5u.com熱心網友回復：
什么叫異步阻塞.......沒有這種說法.
uj5u.com熱心網友回復：
用事實說話，焦點訪談；用代碼說話，真程式員。
uj5u.com熱心網友回復：
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