C# Dev for Beginners #19: Intro to Multithreading - Threads, Race Conditions, and Why It's Hard
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Video Description
Your code runs on a single thread by default. That's about to change. Multithreading unlocks performance but introduces bugs you've never seen before.
What you'll learn: • What a thread actually is (and isn't) • Why your CPU has multiple cores • Creating threads with new Thread() • Race conditions - the bug that works sometimes • Why shared data + multiple threads = disaster • The lock keyword and thread synchronization • Interlocked operations for atomic updates • Deadlocks - when threads wait forever • Why raw threads are the old way
Key insights: • Threads share memory - that's the problem • Race conditions pass tests, fail production • lock serializes access (one thread at a time) • Interlocked is faster than lock for simple ops • Always lock the same object for shared data • Deadlocks happen when lock order differs • Modern C# uses Tasks, not raw threads
We'll build: • Multi-threaded counter (and watch it break) • Race condition demonstration • Thread-safe counter with lock • Deadlock scenario (and how to avoid it)
Previous Video: More LINQ Power Next Video: Thread-Safe Collections ► Full Playlist: https://www.youtube.com/playlist?list=PLGxFXI4dC2shfDgudNdh1FtSLcAZG0-Ba ► Code Repository: https://github.com/benday-inc/csharp-for-beginners-2025
Finally understand why multithreading is hard? Smash that like button! Subscribe and enable notifications - next up we tackle thread-safe collections! What's your worst race condition story? Tell me in the comments!
#CSharp #Multithreading #Threading #DotNet #Programming #RaceCondition #CodingTutorial #LearnToCode
0:00 Introduction to Multithreading 1:19 Your Code Is Never Really Alone 1:45 Inspecting Threads 2:32 Creating a Thread (The Old Way) 3:22 What Could Possibly Go Wrong? 3:50 Race Condition - The Bug That Hides 4:36 How Lost Updates Happen 5:19 The Solution: Lock Statement 5:42 Interlocked - Lock-Free Speed 6:35 What's Actually Thread-Safe? 7:26 Deadlock - When Locks Lock Up 8:19 Threading Don'ts 9:27 Threading Is Genuinely Hard 9:54 Thread-Safe Collections Preview 10:37 Q: When Do I Really Need To Worry About Threading? 11:32 Key Takeaways 12:35 Practice Challenge
Video Info
- Duration: 14:03
- Published: December 12, 2025
