Questions tagged [thread-safety]
A piece of code is thread-safe if it only manipulates data structures in a way that allows consistent execution of this code by multiple threads.
523
questions
49
votes
5
answers
15k
views
Thread-Safe and Lock-Free - Queue Implementation
I was trying to create a lock-free queue implementation in Java, mainly for personal learning. The queue should be a general one, allowing any number of readers and/or writers concurrently.
Would you ...
- 1,301
40
votes
1
answer
4k
views
Recursive shared_mutex implementation
I found myself in need of a Readers-Writer mutex. With C++17 TR2 support not yet available in our compiler, I set out to implement std::shared_mutex so that we have ...
- 16.5k
36
votes
1
answer
21k
views
Extension methods to make ConcurrentDictionary GetOrAdd and AddOrUpdate thread safe when using valueFactory delegates
The ConcurrentDictionary<T,V> in .NET 4.0 is thread safe but not all methods are atomic.
This points out that:
... not all methods are atomic, ...
- 500
36
votes
1
answer
1k
views
Making a generic NSMapTable replacement written in Swift thread-safe
This is a follow-up to this question.
While discussing some details about the code I posted there, I came upon a problem with thread-safety. After searching and trying different things, I reached a ...
- 581
24
votes
2
answers
15k
views
Thread pool worker implementation
As an exercise in using C++11 features I decided to make a thread pool class.
I would like to have a review on the code with focus on:
Standards compliance / Portability issues / Best practices
...
- 16.5k
22
votes
5
answers
36k
views
A TaskScheduler that always run tasks in a specific thread
The following is an TaskScheduler that always run tasks in a thread it maintains.
When created, a name of the thread was specified. Once you schedule the first task,...
- 495
22
votes
2
answers
57k
views
Creating a thread-safe list using a Lock object
Will this code qualify for a truly thread-safe list? It is using the Lock object.
...
- 404
22
votes
1
answer
25k
views
Thread-safe concurrent FIFO queue in C++
Is this the correct way to implement a thread-safe concurrent FIFO queue in C++? It requires passing unsigned char* arrays of binary data.
Thread Safe Concurrent ...
- 615
22
votes
2
answers
25k
views
Thread-safe Singleton class
I have created this class to simulate a thread-safe Singleton.
Have I missed anything?
...
- 321
21
votes
3
answers
16k
views
Determining if a connection has been made to a communications device
I am unsure if my use of Monitor.Wait and Monitor.Pulse is correct. It seems to work alright, but there is a nagging doubt I am ...
- 343
20
votes
1
answer
1k
views
Messed up Elevator Management System
In light of our current community-challenge I decided to build an Elevator Management System.
Initially I intended to program the EMS like a real-time operating system and the elevators as finite-...
Mast♦
- 13.1k
18
votes
2
answers
2k
views
Thread-safe prime number source
I am working on some multi-threaded code that requires a prime-number source.
The following code keeps an array of primes in memory, extending it as needed. It works in the 'int' domain, being ...
- 97.3k
16
votes
4
answers
3k
views
Throttling class
The idea of this class is that several threads are sending data over a network and each thread are sharing the same instance of this class and before sending N bytes over the network each thread is ...
- 193
16
votes
1
answer
6k
views
Lock-free multiple-consumer multiple-producer queue
The code below implements an intrusive lock-free queue that supports multiple concurrent producers and consumers.
Some features:
Producers and consumers work on separate ends of the queue most of ...
- 161
15
votes
3
answers
40k
views
Generic, thread-safe MemoryCache manager for C#
Using this question as a base, and using some of the advice in the answers, I wanted to build out something that would be generic, thread-safe, and easy to use for at least one current and several ...
- 253
15
votes
5
answers
17k
views
15
votes
2
answers
1k
views
Concurrency limit map in Go
Task: per host concurrency limits for web crawler (map[string]Semaphore).
I considered chan struct{} (chan bool) approach, but ...
- 251
15
votes
1
answer
1k
views
C++11 Threadpool
I have developed a threadpool using the standard c++11 features and am looking for feedback.
Right now I think the implementation is pretty solid, but as I recently learned about multithreading I'm ...
- 345
13
votes
2
answers
5k
views
Implementation of a Thread Pool in C++
I wanted to implement a thread pool to test my knowledge of various modern C++ features. The end result could be better, but I need a review as I'm not sure about delicate things especially regarding ...
- 233
13
votes
1
answer
9k
views
Thread-Safe Integer Sequence
I would like to give an Integer to whatever demands it. For that I use the following code
...
- 315
13
votes
2
answers
572
views
Thread-safe large text buffer
This is part of one of my projects called largetext, which actually stemmed from a question on Stack Overflow. The goal is to provide access to a very large text file as a ...
- 1,743
12
votes
2
answers
35k
views
Add/Remove items thread-safely in List<T>
Recently I had to lock collections (of type List<T>) when items were added or removed. Because several collections were used in given code instead of creating ...
- 287
12
votes
1
answer
18k
views
12
votes
2
answers
229
views
Thread safety/Transaction enforcer
I have some legacy classes written without thread safety in mind. Instances of these classes are now being accessed in a multithreaded context in a thread-un-safe manner. Cue chaos.
To fix this I ...
- 16.5k
11
votes
1
answer
9k
views
Concurrent HashSet
I've recently been using HashSet and locking on each method, I found this to not only be a lot of work (was using it in a lot of places) but I started to see inconsistency in my code.
I later decided ...
- 119
11
votes
3
answers
1k
views
Memory cache implementation
I have created an open source memory cache called cachew and can be found here:
cachew. I would like your help to make it better.
Regarding the class Cache or its ...
- 964
11
votes
1
answer
607
views
Multithreading class for asynchronous usage of a custom client/server exchange
I've thrown everything I can at this, and I can't get it to lock or crash. My hope is that I have applied the principles correctly. I write client apps in JavaScript, and this is only the 3rd .NET ...
- 353
11
votes
2
answers
2k
views
Thread-safe session manager
Expected behavior of the code below:
There will be one static SessionManager accessed by many threads.
Multiple calls to ...
- 1,883
11
votes
1
answer
7k
views
Timer to poll a Delegate
This is a followup to this where I was initially using a single thread and Thread.Sleep() to poll a delegate. I was recommended to use a timer and the ...
- 472
11
votes
1
answer
318
views
C++ thread-safe averaging
Although having very little C++ experience, I was tasked to implement several statistics objects that are safe to be asynchronous accessed by different threads, that collect data in relatively small ...
- 213
11
votes
3
answers
5k
views
C++ Threaded Logger
What is it?
It's a fairly simple logger which utilises a thread.
How it works
Note: this a pretty terrible explanation, perhaps it would be easier to look at the code.
The logger class is a ...
- 113
11
votes
1
answer
2k
views
Do not share same socket between two threads at the same time
I have a code in which I am dealing with sockets and I need to make sure that I don't share same socket between two threads. In my below code, I have a background thread which runs every 60 seconds ...
- 1,647
11
votes
1
answer
1k
views
Utilization of the Multiton pattern
See Wikipedia - Multiton Pattern for details on the intent.
Here's the class:
...
- 2,053
10
votes
4
answers
9k
views
AsyncDictionary - Can you break thread safety?
This class is an Async/Await wrapped Dictionary. Of course it doesn't technically implement IDictionary, but the functionality is basically the same as an IDictionary. It achieves similar ...
10
votes
2
answers
6k
views
Using synchronized blocks and volatile variables to ask a Java thread to terminate gracefully
Edit: Just to clarify, this isn't my original code, I've simplified it to make it smaller/easier to understand what I'm trying to do.
It's my first time working with threads in Java, and I was ...
- 103
10
votes
2
answers
3k
views
Will this Circuit Breaker catch fire?
I was going to post this code as an answer to a recent question, but I wrote this code a little while ago (like, a year ago; if I recall correctly I wrote this after reading this article) and I'd like ...
- 75k
10
votes
1
answer
53k
views
Writing to file in a thread safe manner
I'm writing Stringbuilder to file asynchronously. This code takes control of a file, writes a stream to it and releases it. It deals with requests from asynchronous operations, which may come in at ...
- 647
10
votes
2
answers
7k
views
Abuse/Misuse of C# BackgroundWorker?
I have finished a program, and it does what I want it to do, but I feel I am "doing it wrong", even though it's seemingly efficient enough. I have prepared a small example of what I feel I am handling ...
- 103
10
votes
2
answers
30k
views
Synchronous and asynchronous behavior for client
I am working on a project in which I am supposed to make synchronous and asynchronous behavior of my client.
The customer will call our client with a userId and we ...
- 1,647
10
votes
3
answers
32k
views
Correct way to delete elements from a ConcurrentDictionary with a predicate
I have written a caching wrapper class for ConcurrentDictionary. Basically it has a timer that checks if items are expired and removes them. Since ConcurrentDictionary does not have RemoveAll method ...
10
votes
1
answer
2k
views
Platform independant thread pool
v2 of this question is here and v3 is here
To get a better understanding of C++11/C++14, I thought I would develop a thread pool, even if it has been done to death!
The only dependency outside of ...
- 432
10
votes
2
answers
778
views
Sending SMS through twilio from play framework
I am trying to send SMS using Twilio with Scala 2.10 in Playframework 2.2, but this code is looking odd to me, maybe due to lots of conditions. I'm sure it needs some important reviews.
...
10
votes
1
answer
4k
views
Portable C++ boost::interprocess::mutex
I was looking for long time around to have a portable robust solution for multiprocessing synchronization. Who touche this things know that good solution are boost::iterprocess named sync objects.
...
- 101
9
votes
3
answers
11k
views
Implementing an asynchronous mutex in C#
I wrote a simple synchronization primitive that I can use with async operations on an external REST service so that I don't call it twice from different threads and have one call fail due to not ...
- 193
9
votes
1
answer
3k
views
A thread-safe priority queue keeping its elements unique
This class is intended to be used in situations where queue.Queue does not suffice, because the following two properties are needed.
Every item in the queue can ...
- 586
9
votes
2
answers
7k
views
Simple dispatcher implementation
I need a simple dispatcher implementation(invoke methods on one thread from many threads)
once you dispatch method curent thread should wait for results, so I'm thinking about something like this:
<...
- 249
9
votes
2
answers
10k
views
Simple C++ thread pool
I wrote a minimalistic thread pool using some C++11 features. I've used it on two projects so far and it has worked fine, but when I ran the code on my laptop, I believe that my thread pool might be ...
- 93
9
votes
2
answers
961
views
Multithreaded bogosort in Rust
For some quick context, I'm fairly new to Rust and decided to give myself a difficult-but-attainable task of implementing a sorting algorithm. I chose bogosort (or stupid-sort, shuffle-sort, whatever ...
- 93
9
votes
2
answers
16k
views
Thread-safe std::map accessor
After learning that std::map containers are not inherently atomic and therefore not thread-safe (check out this related Stack Overflow question and usage example), ...
- 191