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Questions tagged [mutex]

A mutex ("mutual exclusion") is a mechanism to ensure integrity when the same data or resource is accessed (in particular, changed) concurrently from several threads.

A mutex ("mutual exclusion") is a mechanism to ensure integrity when the same data or resource is accessed (in particular, changed) concurrently from several threads.

Usually when the term mutex is used, it refers to a synchronisation primitive functionally identical to a binary semaphore. As OS-level synchronisation is often rather expensive due to context switching, busy-wait solutions based on atomic operations (e.g. mutex or critical section) exist.

See also:

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Plural form of word "mutex"

What is the correct plural form of the portmanteau mutex. Is it mutexes or mutices?
fmark
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Monitor vs Mutex

I read that mutex is a semaphore with value 1 (binary semaphore) used to enforce mutual exclusion. I read this link Semaphore vs. Monitors - what's the difference? which says that monitor helps in achieving mutual exclusion. Can someone tell me the…
Zephyr
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Are mutex lock functions sufficient without volatile?

A coworker and I write software for a variety of platforms running on x86, x64, Itanium, PowerPC, and other 10 year old server CPUs. We just had a discussion about whether mutex functions such as pthread_mutex_lock() ... pthread_mutex_unlock() are…
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WPF Single Instance Best Practices

This is the code I implemented so far to create a single instance WPF application: #region Using Directives using System; using System.Globalization; using System.Reflection; using System.Threading; using System.Windows; using…
Tommaso Belluzzo
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How pthread_mutex_lock is implemented

I am just curious to know how functions related to synchronization between threads are implemented inside Unix. For example, what happens when I call pthread_mutex_lock? Are there any pointers in use? A reference to the source code would really…
avd
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Does pthread_cond_wait(&cond_t, &mutex); unlock and then lock the mutex?

I m using pthread_cond_wait(&cond_t, &mutex); in my program and I m wondering why this function needs as a second parameter a mutex variable. Does the pthread_cond_wait() unlock the mutex at the beginning (beginning of the execution…
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std::mutex performance compared to win32 CRITICAL_SECTION

how does the performance of std::mutex compared to CRITICAL_SECTION? is it on par? I need lightweight synchronization object (doesn't need to be an interprocess object) is there any STL class that close to CRITICAL_SECTION other than std::mutex ?
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mutex.lock vs unique_lock

When should I prefer the first piece of code to the second, and do they have fundamental differences std::mutex mtx; mtx.lock(); ... //protected stuff mtx.unlock(); ... //non-protected stuff mtx.lock(); ... //etc and std::mutex…
Morgan Fouque
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Pthread mutex assertion error

I'm encountering the following error at unpredictable times in a linux-based (arm) communications application: pthread_mutex_lock.c:82: __pthread_mutex_lock: Assertion `mutex->__data.__owner == 0' failed. Google turns up a lot of references to that…
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Using Pointers in a for loop

I'm struggling to understand why I have a bug in my code in one state but not the other. It's been a while since I've covered pointers, so I'm probably rusty! Basically I have a repository structure I'm using to store an object in memory, that has a…
Simon
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Is using a Mutex to prevent multiple instances of the same program from running safe?

I'm using this code to prevent a second instance of my program from running at the same time, is it safe? Mutex appSingleton = new System.Threading.Mutex(false, "MyAppSingleInstnceMutx"); if (appSingleton.WaitOne(0, false)) { …
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Advantages of using condition variables over mutex

I was wondering what is the performance benefit of using condition variables over mutex locks in pthreads. What I found is : "Without condition variables, the programmer would need to have threads continually polling (possibly in a critical…
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boost scoped_lock vs plain lock/unlock

I'm going to use boost::mutex from boost/thread/mutex.hpp. There are several ways to lock/unlock mutex: with scoped_lock, unique_lock, lock_guard, mutex's member functions ::lock() and ::unlock() and nonmember functions lock() and unlock(). I…
Max
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Use std::lock_guard with try_lock

Is there a way I can tell std::lock_guard to call try_lock instead of lock when it acquires the mutex? The only way I could think of is to use std::adopt_lock: if (!_mutex.try_lock()) { // Handle failure and return from the…
Mr. Anderson
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Object synchronization method was called from an unsynchronized block of code. Exception on Mutex.Release()

I have found different articles about this exception but none of them was my case. Here is the source code: class Program { private static Mutex mutex; private static bool mutexIsLocked = false; static void Main(string[] args) { …
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