characteristics of the wait () and notify () methods determine that they are often used with synchronized methods or blocks.A comparison between them and the operating system's interprocess communication mechanism reveals their similarity: the Synchronized method or block provides functionality similar to the operating system primitives, and their execution is not interfered by the multithreading mechanism, which is equivalent to block and wake up Primitives (this pair of methods are declared a
algorithms) on the operating system, and to solve a variety of complex inter-threading communication problems.The Wait () and notify () methods are finally explained in two points:First: Calling the Notify () method causes the unblocked thread to be randomly selected from the thread that was blocked by calling the wait () method of the object, and we cannot predict which thread will be selected, so be careful when programming, and avoid problems with
Synchronized). Their combination allows us to implement an array of sophisticated inter-process communication algorithms (such as semaphore algorithms) on the operating system, and to solve a variety of complex inter-threading communication problems.The Wait () and notify () methods are finally explained in two points:First: Calling the Notify () method causes the unblocked thread to be randomly selected from the thread that was blocked by calling th
mask word in the process, where the third parameter is passed NULL because it does not care about its original signal shielding word for (;;) {sigpending (PSet); Printsigset (PSet); Sleep (1); } return 0;}voidHandlerintSIG) {printf ("recv a sig=%d\n", SIG);}Compile run:From the results, the SIGINT signal, as added to the signal screen Word is 1, so it will be blocked off, and you can see the SIGINT corresponding bit is also printed as 1."description": The corresponding bit of SIGINT refers
function, Snap to sigquit, jump to function pointer Sig_quit executeSigemptyset (newmask);//Initialize semaphore setSigaddset (newmask, sigquit);//Add Sigquit to the semaphore setSigprocmask (Sig_block, newmask, oldmask);//The Newmask in Sigquit is blocked off,and save the current signal screen word to OldmaskSleep (5);//Sleep for 5 seconds,here is the explanation: During 5s sleep, any sigquit signal will be blocked, if you receive any keyboard quit signal in 5s, then this information will be p
system's interprocess communication mechanism reveals their similarity: the Synchronized method or block provides functionality similar to the operating system primitives, and their execution is not interfered by the multithreading mechanism, which is equivalent to block and wake up Primitives (this pair of methods are declared as synchronized). Their combination allows us to implement an array of sophisticated inter-process communication algorithms (such as semaphore algorithms) on the operati
First, batch new users1, you first need to define a variable2, select that looping statement to create the script.3, what command to use to perform "echo RedHat | passwd--stdin $user "[Email protected] ~]# VI user.sh#!/bin/bash#auth by Tony#date 2017-11-03For NUM in {1..9}; DoUser=user$numUseradd $userecho RedHat | passwd--stdin $userDoneSecond, bulk delete users1, the first need to create a new User.txt document to delete the user name to write to it;2, need to delete the user's command, userde
causes the unblocked thread to be randomly selected from the thread that was blocked by calling the wait () method of the object, and we cannot predict which thread will be selected, so be careful when programming and avoid problems with this uncertainty. (2) In addition to notify (), there is also a method Notifyall () can also play a similar role, the only difference is that the call to the Notifyall () method will be called by the Wait () method
Today, when you open a page in the browser, suddenly eject the "Network Connection Error" dialog box, display "Network connection error (error code 118), please use 360 Network emergency box to check the Internet", but with the first aid box checked the network, or can not be resolved, shuxin still can not solve, The repeated tests finally solved the problem.
One: First we check the network, whether the network is unblocked, if the networ
Lamp Environment --linux DirectoryLAMP Environment --linux 1One, file Operation 31 , Find File Lookup 32 , DF disk partition Information 33 , du Statistics File size information 44 , Mount Disk 5Second, configure the network 61 , configuration Files 62 , starting the network 63 , ifconfig View network Information 74 , Ping test the network is unblocked 75 , Linux Firewall 9Third, FTP Service 101 , FlashFXP Software Use 102 , vsftpd Service 12Four, LAM
In Windows, you can use the ping command in CMD to detect network connection conditions, as follows:When the network connection is normal:When the network is not connected:In Java, you can call the ping command to determine whether the network is connected properly:Package Module.system.common;import Java.io.bufferedreader;import Java.io.ioexception;import java.io.InputStream; Import java.io.inputstreamreader;/** * Determine network connection status. * @author NAGSH * */public class Netstate
First: Check the physical connection is unblocked.
Configure the IP address on the network adapter connected to the client and the server to ensure that the IP address gigabitethernet1/0/0 the server-side interface is on the same network segment. Ping gigabitethernet1/0/0 interface from the client IP address, if you can ping, then the connection is unblocked, then the physical line failure can be excluded
The testing process found that JS data contains plus + via AJAX to the background when the connection error, delete +, link unblocked, it is this problem, the plus to escape
Yesterday someone proposed a bug, said "B + Detective" and "Detective c+" can not see, I was very depressed, because other resources can be played, why this can not play, and the name of the movie I have been converted, in constant debugging, found that the URL address movie name
on the Internet when we encounter such an access failure?
First of all, check the staff Xiao Meng's workstation for physical connection is correct. In this regard, we may wish to open the local workstation's IE browser window, and in the window address bar to enter the wireless router's background management address, click the ENTER key to open its background login interface, and then correctly enter the administrator account and password, access to the wireless router background management in
of the synchronization feature class EventWaitHandle (subclass AutoResetEvent, ManualResetEvent), Semaphore and mutexes inherit from WaitHandle, so the underlying principle is consistent, maintaining a system kernel handle. But we still need to simply distinguish between the three types of classes. The EventWaitHandle maintains a Boolean type object (called a "block State") produced by the kernel, and if its value is false, the thread waiting on it is blocked. You can call the type's set met
TTL specifies the ping group time domain, which is the number of gateways that should elapse before stopping the reached address;
The type of the-V TOS service;-R count indicates the number of rotations (go and back) to record the route;
-S count specifies the time for each round of routing when the-r parameter is used;
-j Host-list Specifies the route that you want to group;
K-Host-list and-j parameters are basically the same, just can not use the additional host;
-w timeout Specifies the time
state to an executable state:
1 The sleeping thread has passed the specified sleep time
2 The thread is waiting for the I/O operation has completed
3 Other threads release the lock that this thread is waiting for (or because the timeout thread is automatically unblocked)
4 other threads signal that the trigger condition that this thread is waiting for has changed (or because the timeout thread is automatically un
connection removal function ( this need in the implementation, to ascertain the function of the net gate and the net gate can have much impact on the network . After a test, the most positioning to the network gate should be a time to remove the function of the TCP connection (because if the business is more frequent, the database connection is unblocked, as long as the business idle situation will appear this problem).
Problem Solving Ideas:
First s
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