𝐃𝐚𝐭𝐚 𝐑𝐚𝐜𝐞 and 𝐑𝐚𝐜𝐞 𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧𝐬

🔥In this post, I’ll cover key 𝐜𝐨𝐧𝐜𝐮𝐫𝐫𝐞𝐧𝐜𝐲 concepts related to multithreaded programming in C++, which are also commonly asked in #interview_questions.

1️⃣ 𝐃𝐚𝐭𝐚 𝐑𝐚𝐜𝐞𝐬
2️⃣ 𝐑𝐚𝐜𝐞 𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧𝐬

Before continuing, let’s understand the following concepts:

⭕ There are 𝐭𝐰𝐨 basic approaches to concurrency:
☑️ Concurrency with 𝐦𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐩𝐫𝐨𝐜𝐞𝐬𝐬𝐞𝐬
☑️ Concurrency with 𝐦𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐭𝐡𝐫𝐞𝐚𝐝𝐬

⭕ 𝐂𝐨𝐧𝐜𝐮𝐫𝐫𝐞𝐧𝐜𝐲 𝐰𝐢𝐭𝐡 𝐌𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐏𝐫𝐨𝐜𝐞𝐬𝐬𝐞𝐬:
This approach involves dividing an application into multiple 𝐬𝐢𝐧𝐠𝐥𝐞-𝐭𝐡𝐫𝐞𝐚𝐝𝐞𝐝 𝐩𝐫𝐨𝐜𝐞𝐬𝐬𝐞𝐬 that run simultaneously, much like running a web browser and a word processor at the same time. These separate processes communicate through inter-process communication channels such as signals, sockets, files, or pipes.

⭕ 𝐂𝐨𝐧𝐜𝐮𝐫𝐫𝐞𝐧𝐜𝐲 𝐰𝐢𝐭𝐡 𝐌𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐓𝐡𝐫𝐞𝐚𝐝𝐬 (the focus of this post):
This approach involves running multiple threads within 𝐚 𝐬𝐢𝐧𝐠𝐥𝐞 𝐩𝐫𝐨𝐜𝐞𝐬𝐬. A process is the operating system’s abstraction for a running program. In modern systems, a process can consist of multiple execution units, called threads, each running in the context of the process. All threads in a process share the same address space, so most data can be accessed directly by all threads—global variables remain global, and pointers or references to data can be shared among threads.

✅ 𝐃𝐚𝐭𝐚 𝐑𝐚𝐜𝐞𝐬:
A data race, as defined by the 𝘊++ 𝘚𝘵𝘢𝘯𝘥𝘢𝘳𝘥, combines two key aspects:
💠1️⃣ 𝐒𝐡𝐚𝐫𝐢𝐧𝐠: More than one thread accesses the same memory location.
💠2️⃣ 𝐌𝐮𝐭𝐚𝐭𝐢𝐨𝐧: At least one thread writes to that memory location.

If these accesses occur simultaneously without proper synchronization primitives—such as mutexes or locks—this results in unpredictable or 𝐮𝐧𝐝𝐞𝐟𝐢𝐧𝐞𝐝 𝐛𝐞𝐡𝐚𝐯𝐢𝐨𝐫. Data races typically arise because threads in a concurrency model share the same memory space.

✅ 𝐑𝐚𝐜𝐞 𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧𝐬:
A race condition is 𝐚 𝐬𝐞𝐦𝐚𝐧𝐭𝐢𝐜 𝐟𝐥𝐚𝐰 that occurs when the 𝐭𝐢𝐦𝐢𝐧𝐠 or 𝐨𝐫𝐝𝐞𝐫 of events affects the correctness of a section of code. In concurrency, a race condition arises when the outcome depends on the relative ordering of operations across two or more threads—the threads "𝐫𝐚𝐜𝐞" to perform their operations. Race conditions are challenging to detect because they depend on 𝐭𝐡𝐞 𝐢𝐧𝐭𝐞𝐫𝐥𝐞𝐚𝐯𝐢𝐧𝐠 of thread executions.

➡️ 𝐓𝐋;𝐃𝐑:
Data races concern access to the same memory location, while race conditions concern the correctness of code execution.

➡️ 𝐑𝐞𝐬𝐨𝐮𝐫𝐜𝐞𝐬:
1️⃣ API Design for C++ (2nd Edition) by Martin Reddy
2️⃣ C++ Concurrency in Action: Practical Multithreading (2nd Edition) by Anthony Williams
3️⃣ Concurrency with Modern C++ by Rainer Grimm
4️⃣ Modern Operating Systems (5th Edition) by Andrew S. Tanenbaum and Herbert Bos

I hope you enjoy reading it! 🌸

#cpp #multithreading #concurrency #cplusplus #learncpp #IloveCpp 💗 #programming #code #softwaredevelopment #codinglife #moderncpp #templateprogramming #cplusplus17 #cplusplus20 #cppdeveloper #cppcommunity