multiprocessing.Lock is implemented using a Semaphore object provided by the OS. On Linux, the child just inherits a handle to the Semaphore from the parent via os.fork. This isn’t a copy of the semaphore; it’s actually inheriting the same handle the parent has, the same way file descriptors can be inherited. Windows on the other … Read more
multiprocessing.Lock is implemented using a Semaphore object provided by the OS. On Linux, the child just inherits a handle to the Semaphore from the parent via os.fork. This isn’t a copy of the semaphore; it’s actually inheriting the same handle the parent has, the same way file descriptors can be inherited. Windows on the other … Read more
From the C# language reference here: In general, avoid locking on a public type, or instances beyond your code’s control. The common constructs lock (this), lock (typeof (MyType)), and lock (“myLock”) violate this guideline: lock (this) is a problem if the instance can be accessed publicly. lock (typeof (MyType)) is a problem if MyType is … Read more
Lock is a questionable idea in JS which is intended to be threadless and not needing concurrency protection. You’re looking to combine calls on deferred execution. The pattern I follow for this is the use of callbacks. Something like this: var functionLock = false; var functionCallbacks = []; var lockingFunction = function (callback) { if … Read more
Since 9.6 this is a lot easier as it introduced the function pg_blocking_pids() to find the sessions that are blocking another session. So you can use something like this: select pid, usename, pg_blocking_pids(pid) as blocked_by, query as blocked_query from pg_stat_activity where cardinality(pg_blocking_pids(pid)) > 0;
Short answer: In an out-of-order processor the load-store queue is used to track and enforce memory ordering constraints. Processors such as the Alpha 21264 have the necessary hardware to prevent dependent load reordering, but enforcing this dependency could add overhead for inter-processor communication. Long answer: Background on dependence tracking This is probably best explained using … Read more
You can use these functions LockWorkStation GetLastInputInfo see this code, you must add a timer to your form, and set this.timer1.Enabled = true; using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Runtime.InteropServices; namespace WindowsFormsApplication9 { internal struct LASTINPUTINFO { public uint cbSize; public uint dwTime; } public partial … Read more
As said, you could use FLock. A simple example would be: //Open the File Stream $handle = fopen(“file.txt”,”r+”); //Lock File, error if unable to lock if(flock($handle, LOCK_EX)) { $count = fread($handle, filesize(“file.txt”)); //Get Current Hit Count $count = $count + 1; //Increment Hit Count by 1 ftruncate($handle, 0); //Truncate the file to 0 rewind($handle); //Set … Read more
After doing some effort I did it (My app was working on perfect till android 2.3 but got db lock error when I used to run it on HoneyComb tablet). I did using Semaphores (using lock in critical sections). Example 1 public class DbExp extends SQLiteOpenHelper{ public static String Lock = “dblock”; private static final … Read more
For cross-process locking in C#/.Net, you can use a named system Mutex.