wdm multiplexing

data to the client segment at intervals, so_keepalive is insufficient. Because the so_keepalive option refers"There is no data exchange in any direction of this interface". In the Linux 2.6 series, the above understanding is that as long as the set interface that opens the so_keepalive option detectsData transmission or data receivingIt is considered as data exchange. That is, in the case of abnormal disconnection (the server does not receive the "fin" or "rst" packet), the upper-layer program

the ready events detected by the kernel. this greatly improves the efficiency of the application's index-ready file descriptor. Differences between poll and epoll /* How to index the ready file descriptor returned by poll */int ret = poll (FDS, max_event_number,-1 ); /* You must traverse all registered file descriptors and find the ready */For (INT I = 0; I Epoll's LT and ET Modes Epoll has two modes for file descriptor operations: Lt and ET. when you register an epollet event on a file descri

The main implementation of multiplexing Io is the int select (INT maxfd, fd_set * readset, fd_set * writeset, fd_set * effect_set, const struct timeval * timeout) function. Generally, we only set one in readset, writeset, and effectset, and the other two are null. The system monitors data from 0 to maxfd.When any file descriptor is ready in the corresponding set, the Select function returns. In this case, the content of readset, writeset, and inittset

1. Introduction Multiplexing I/O model (select) is the most commonly used I/O model in UNIX/LINUX. It can also be used as a synchronous I/O model in Windows. This article provides a simple implementation of the I/O model to process multiple clients (in the main thread. 2. About select The select I/O model is an asynchronous I/O model. By default, Linux/WinNT supports 64 client sockets in a single thread. This I/O model mainly involves the following f

{ 10 Int Sockfd, N; 11 Char Buf [maxline]; 12 Sockfd = socket (af_inet, sock_stream, 0 ); 13 Struct Sockaddr_in servaddr; 14 Memset ( servaddr, 0 , Sizeof (Servaddr )); 15 Servaddr. sin_family = af_inet; 16 Servaddr. sin_port = htons ( 10001 ); 17 Inet_ton (af_inet, " 127.0.0.1 " , Servaddr. sin_addr ); 18 19 Connect (sockfd ,( Struct Sockaddr *) servaddr, Sizeof (Servaddr )); 20 While ( 1 ) 21 { 22 Printf ( " Type some words... \ n " ); 23 Scanf ( " % S " , Buf

code is as follows: // Clientfd [] indicates the number of socket descriptor groups of the client. Assume that the array size is Max and all socket descriptors of the client are set to non-blocking. For (I = 0; I { Int N; If (n = read (clientfd [I], Buf, szie)> 0) { // Send response to client in here. } } The code here does not seem to be much different from the above Code. In fact, there is a big difference. The difference is that non-blocking Io is used for the entire interaction process, th

socket descriptors (file descriptors) generated by the TCP server can be summarized into a set of readable file descriptors. When we detect the sock socket of listen () to establish the connection accept (), if the confirmation is normal, that is, we accept () the resulting file descriptor, it is determined that this is a client/server connection link. Then we use the relevant function operation to carry out the information transmission, Timeout represents the time at which the query wa

, which returns the entire user-registered collection of events, so the time complexity of the application index-ready file is O (n). c) poll uses the Nfds parameter to specify the maximum number of file descriptors and events to listen to, which can reach the maximum file descriptor that the system allows to open, which is 65535. d) can only work in the LT mode. 5, poll 1) Poll, unlike Select, passes a POLLFD array to the kernel to pass events that need attention, so there is no limit to the

operation () { System.out.println (" Concreteimpa operation ");} } Package Bridge; Public class extends Imp { @Override publicvoid operation () { System.out.println (" CONCRETEIMPB operation ");} } Package Bridge; Public Abstract class IMP { publicabstractvoid operation ();} Package Bridge; Public class extends Abstraction { publicstaticvoid main (string[] args) { abstraction Abstraction=new refinedabstraction (); Abstraction.setimp

Secret, write only steps here, do not write execution results: 0. Control file backup alter session set tracefile_identifier= ' Bak_control '; ALTER DATABASE backup Controlfile to trace;1. Confirm control File name Select name from V$controlfile;2. Add a new control file path alter system set control_files= ' +data1/dxmy/controlfile/ current.260.820062903 ', ' +data2 ' scope=spfile;3. Close the database, boot to nomount mode srvctl stop database-d orclsrvctl start database-d Orcl-o nomount4. Che

Basic knowledge about SelectA. Select is a system-supplied multiplexed input-output model. It is used to monitor the state changes of multiple file handles.B. The program will stop at select and so on until at least one of the monitored file handles has changed state.C. File handle is an integer Function 650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/82/01/wKiom1dG_begWcr6AABAizofHMA736.png "title=" capture. PNG "alt=" Wkiom1dg_begwcr6aabaizofhma736.png "/>A. ParametersNfds:

This is a creation in Article, where the information may have evolved or changed. Introduction:This paper describes a network protocol processing framework which is implemented in go language, which is suitable for the go language concurrency model, and provides the framework code implementation. The author uses this framework for protocol processing in online game servers, but it can also be used in other areas. Application background:In the design of network game server, it is common to encou

In the ListView item, when a checkbox is clicked, the user clicks on the first checkbox, drags down, and finds that the checkbox below is not selected, likes and dislikes! Quite simply, this is because of the problem with the Convertview reuse, which usually does not allow the checkbox to remember his own state, choose to remember the status of the checkbox in the business bean, and add a filed to the business bean:Private Boolean checked;Use the Gettag method of view to get Viewholder:Lv_task_m

the corresponding file descriptor can be read (including a graceful shutdown of the peer socket);Epollout: Indicates that the corresponding file descriptor can be written;Epollpri: Indicates that the corresponding file descriptor has an urgent data readable (this should indicate the arrival of out-of-band data);Epollerr: Indicates an error occurred in the corresponding file descriptor;Epollhup: Indicates that the corresponding file descriptor is hung up;Epollet: Set Epoll to edge triggered mode

server Import Socketsk1 = Socket.socket () sk1.bind ((' 127.0.0.1 ', 8001)) Sk1.listen () Sk2 = Socket.socket () sk2.bind ((' 127.0.0.1 ', 8002)) Sk2.listen () Sk3 = Socket.socket () sk3.bind (' 127.0.0.1 ', 8003)) Sk3.listen () InP = [Sk1,]import selectwhile true:print (len (INP)) #r_list receive the INP parameter if there is a user to link it will sense, #w_lis T can write a fixed handle for listening if [SK1,SK3] #e_list listen for the handle of the error, if any, remove it, such as the follo

assigned to a final object directly, but it is possible to change the value of a reference object, such as1 PackageCom.chenlei.study.thinkinginjava;2 3 Public classFinal {4 PublicString string = "haha";5 Public FinalString astring =string;6 Public Static voidMain (string[] args) {7Final Final1 =NewFinal ();8final1.string = "123";9 System.err.println (final1.astring);Ten } One } A /** - * Output: - * haha the */ The final data can be initialized at the time of declaration

high Python SelectThe function that calls Select is R, W, E = select.select(rlist, wlist, xlist[, timeout]) , the first three parameters are three lists, the objects in the array are waitable object : Both the file descriptor of the whole number, or an object that has the method of returning the file descriptor (descriptor) fileno() ; rlist: Waiting for the list to be read ready wlist: Waiting for the list to be written ready errlist: Wait for the list of "exceptions"

to allocate space, as in the example above. Benefit: The Java compiler will have a garbage collector to automatically free up memory when B1 is not available.(2) calls (with parameters) in the same class as the package:1Package test1; 3 public class D 4 { 5 public int getDate ( Int D1) { 7 int d = D1; 8 return D; 9 }10} 1PackageTest1;23PublicClass e 4 { 5 6 public static void Main (string[] args) 7 { 8 D da = new D (); 9 int D1 = da.getdate (1) ; 10 System.out.println (

Ctrl + B and then press "? "To view all supported commands. Create a new Tmux session command: Press Ctrl + B and then press "c" to create a new session. On the new session page, you can see a green Tmux session record at the bottom. The session marked with * indicates the current session. You can switch between the listed sessions, press Ctrl + B, press "w", then use the arrow to move to the session you need, and press Enter, you can switch to the corresponding session. To exit the current s

The reuse of lists in Android improves the efficiency of the app, but the attendant problem of reuse is always a headache for programmers, aThe bug was not found the night before. I will give my own experience in this area to contribute for your reference:Question 1: What is multiplexingReuse refers to the reuse view, and the data of the bound view is changed.Issue 2: Reusing a scene that appearsIn adapter, if the data of the view is bound if there is an if judgment, many people forget to add el