C++ development experience sharing: practical experience in C++ concurrent programming

C Development experience sharing: Practical experience of C concurrent programming

Introduction:
In today's era of rapid technological development, multi-core processors have become the core of computer systems. mainstream. Therefore, concurrent programming has become one of the necessary skills for developers. In the world of concurrent programming, C is widely used for its powerful multi-threading support and efficient performance. However, concurrent programming is not easy and requires developers to master some practical experience. This article will share some of my practical experience in concurrent programming in C development.

1. Choose the correct thread library
C itself does not have a built-in thread class, but uses a third-party library for thread programming. Therefore, the correct choice of thread library is the key to successful concurrent programming. Common C thread libraries include the POSIX thread library (pthread) and std::thread in the C 11 standard library. The POSIX thread library is cross-platform, but it is cumbersome to use and requires manual management of thread creation, destruction, and synchronization. std::thread is a new feature introduced in C 11, which is more concise and easy to use, and provides richer threading functions. Therefore, I prefer to use std::thread for concurrent programming.

2. Reasonable use of mutex locks
In multi-threaded programs, access and modification of shared resources will inevitably be involved. In order to ensure the consistency of shared resources, mutex locks must be used for synchronization. However, improper use of mutex locks can lead to deadlocks or performance degradation. Therefore, the rational use of mutex locks is an important factor in ensuring the correctness and efficiency of multi-threaded programs.

First of all, don't overuse mutex locks, use them only when necessary. The smaller the granularity of the mutex lock, the higher the concurrency. For example, instead of using a global mutex when operating on multiple data members, use a fine-grained mutex to improve concurrency.

Secondly, avoid deadlocks between multiple locks. Deadlock refers to two (or more) threads waiting for each other's lock, which is very common in actual development. To avoid deadlock, try to ensure that the thread only acquires one lock, or acquires multiple locks in a fixed order.

Finally, try to use RAII (Resource Acquisition Is Initialization) technology to manage mutex locks. RAII technology ensures that the mutex lock is released when the scope ends, avoiding the problem of forgetting to release the lock.

3. Pay attention to the use of atomic operations
In addition to mutex locks, atomic operations are also a common method of concurrent programming. Atomic operations are special operations that ensure correctness in a multi-threaded environment. The std::atomic template class is provided in the C 11 standard library to encapsulate atomic operations.

When using atomic operations, you need to follow the following principles. First, only perform atomic operations on single variables, not complex data structures. Secondly, atomic operations themselves are low-level operations. You should try to avoid using atomic operations to implement complex synchronization logic. Instead, use high-level synchronization mechanisms such as mutex locks. Finally, when using atomic operations, you need to pay attention to the scope of application and reduce the frequency of use of atomic operations to improve efficiency.

4. Avoid race conditions
Race conditions are a common problem in multi-threaded programs. When multiple threads operate on the same resource, the correctness of the result depends on the execution order of the threads. To avoid race conditions, there are several strategies you can employ.

First, try to avoid sharing resources. Shared resources are the most likely place to cause race conditions in multi-threaded programming. Therefore, try to privatize resources and reduce sharing. Second, use condition variables for synchronization. Condition variables allow threads to continue executing when a certain condition is met, thus avoiding the thread's busy waiting. Finally, use a sequential consistency model. The sequential consistency model can ensure that multi-threaded programs are executed in a program serialization manner, avoiding race conditions.

Conclusion:
Concurrent programming plays an important role in C development. Correct use of concurrent programming can give full play to the performance of multi-core processors. This article shares some practical experience in C concurrent programming, including choosing the right thread library, rational use of mutex locks, paying attention to the use of atomic operations, and avoiding race conditions. I hope that sharing these experiences can help readers better perform C concurrent programming and improve the performance and correctness of the program.

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