locking | 易学教程

Collection was modified; enumeration operation may not execute. Lock is being used everywhere how possible?

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问题 This is a small program that only i am writing and using. Now i am going to write code of all areas where i use the hashset that caused this problem I don't understand how this is possible. This item is being used only at MainWindow hsProxyList is a hashset HashSet<string> hsProxyList = new HashSet<string>(); the error happened at below iteration lock (hsProxyList) { int irRandomProxyNumber = GenerateRandomValue.GenerateRandomValueMin(hsProxyList.Count, 0); int irLocalCounter = 0; foreach

Proper way to use SyncLock (in general)

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问题 This is a follow-up to a previous question regarding locking on two List(Of T) objects. The answer there was helpful but left me with another question. Suppose I have a function like this: Public Function ListWork() As Integer List1.Clear() ..Some other work which does not modify List1.. List1.AddRange(SomeArray) ..Some more work that does not involve List1.. Return List1.Count End Function which resides in a class that declares List1. In a multithreaded environment, I now understand that I

$ symbol in c++

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问题 I read the following code from an open source library. What confuses me is the usage of dollar sign. Can anyone please clarify the meaning of $ in the code. Your help is greatly appreciated! __forceinline MutexActive( void ) : $lock(LOCK_IS_FREE) {} void lock ( void ); __forceinline void unlock( void ) { __memory_barrier(); // compiler must not schedule loads and stores around this point $lock = LOCK_IS_FREE; } protected: enum ${ LOCK_IS_FREE = 0, LOCK_IS_TAKEN = 1 }; Atomic $lock; 回答1: It is

How To Lock Java Process To Memory? (MLock)

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I found this stack overflow question from 2010: Lock or Pin java process into memory Basically it says the way to lock a java process to memory is by using JNI. The example it points to is a broken link. Now that it's 2013 my question is.. Is there a better way? And is there an example somewhere of someone using mlock in Java? I'm extremely inexperienced with JNI and with C code in general, but quite familiar with Java (although I've NEVER used JNI). Thanks I'm wondering if there's a good java solution that doesn't involve JNI if possible. There isn't. Pinning an application in memory is

MySQL MyISAM table locking

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问题 Does a MySQL MyISAM table gets locked when records are deleted from it? 回答1: MyISAM tables supports table level locking, and yes, a write lock is employed when deleting (or insert & updating) records. For more info, see Internal Locking Methods 来源： https://stackoverflow.com/questions/1951161/mysql-myisam-table-locking

C# threading - Lock Object

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问题 I am trying to lock a "boxed" object in a c# app, is this not possible? class t { System.Object t_x = new object(); public t(int p) { t_x = p; } public void w() { lock (t_x) { for (int i = 0; i < 4; i++) { { t_x = ((int)t_x) + 1; Console.WriteLine(t_x); Thread.Sleep(1000); } } } } } In another class I can start 2 threads: Thread b1 = new Thread(new ThreadStart(t1.w)); b1.Start(); Thread b2 = new Thread(new ThreadStart(t1.w)); b2.Start(); However the portion is not locked. When I lock an

How to test if a thread is holding a lock on an object in C#?

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问题 Is there a way to test if the current thread is holding a monitor lock on an object? I.e. an equivalent to the Thread.holdsLock in Java. Thanks, 回答1: I don't believe there is. There are grotty hack things you could do like calling Monitor.Wait(monitor, 0) and catching the SynchronizationLockException , but that's pretty horrible (and could theoretically "catch" a pulse that another thread was waiting for). I suggest you try to redesign so that you don't need this, I'm afraid. EDIT: In .NET 4

How to understand LockService and implement it correctly?

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问题 Summary of Code I have a Google Apps Script project that is used by around 80 users within a specific domain, however the app is executed by me (ie Publish > Deploy as web app > Execute the app as : Me ). One of the functions of the script is to populate a Google Sheet from a custom form (using HTML Service ) and then notify myself and the submitting user (who is identified through the use of a simple login system and cookies). It has been working fine for about 6 months, however on 1-2

c# lock on reference passed to method - bad practice?

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问题 I have a method similar to: public static void DoSomething (string param1, string param2, SomeObject o) { //..... lock(o) { o.Things.Add(param1); o.Update(); // etc.... } } A few points: Is locking in this way bad practice? Should I lock on a private static object instead? If so, why? 回答1: To minimize side effects, the object being locked on should not be the object being manipulated but rather a separate object designated for locking. Depending on your requirements, there are a few options

SSHClient jsch bufferedinputstream LOCK

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When executing command via SShClient based on jsch session get lock: Exec thread devapp090@1046" prio=5 tid=0x14 nid=NA runnable java.lang.Thread.State: RUNNABLE at java.io.FileInputStream.readBytes(FileInputStream.java:-1) at java.io.FileInputStream.read(FileInputStream.java:220) at java.io.BufferedInputStream.read1(BufferedInputStream.java:256) at java.io.BufferedInputStream.read(BufferedInputStream.java:317) - locked <0x420> (a java.io.BufferedInputStream) at com.jcraft.jsch.ChannelSession.run(ChannelSession.java:245) at java.lang.Thread.run(Thread.java:662) Here how I call client: client