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STD::THREAD: An Introduction to Multi-Threading and Its Application
What’s good, dawgs? Are you ready to dive into some gangster programming topics? Today we are going to talk about an essential and versatile tool for multi-threading in C++, and it’s none other than std::thread! This baby right here is a powerhouse when it comes to multi-threading programming, and we’ll show you why.
What is std::thread, and How Does it Work?
Before we go deep into this topic, let me explain to you fellas what std::thread is. In a nutshell, it’s a library in C++ that allows you to spawn new threads which can run independently of the main thread. In other words, it enables you to create multiple processes that run simultaneously in a program.
Using std::thread is pretty easy, dawgs. All you need to do is add the thread library and call the std::thread constructor while passing the function you want to execute. For example, here’s a simple function that outputs Hello, mate! to the console:
“`
void say_hello() {
std::cout << Hello, mate! << std::endl;
}
“`
And here is how you spawn a new thread:
“`
std::thread t(say_hello);
“`
That's it! Now you have a new thread that runs in parallel with the main thread, and it should output Hello, mate! when you run the program.
Example of std::thread
Here’s a practical example of how you can use std::thread to parallelize a task. Let’s say you have a function that sorts an array in ascending order, and you want to measure how long it takes to complete it. Without multi-threading, you would run the function sequentially and measure the time it takes like this:
“`
auto start = std::chrono::system_clock::now();
sort_array(my_array, array_size);
auto end = std::chrono::system_clock::now();
auto elapsed_seconds = std::chrono::duration_cast(end – start).count();
“`
On the other hand, with std::thread, you can create multiple threads and divide the array into sub-arrays to sort them simultaneously. Here’s how you would do it:
“`
auto start = std::chrono::system_clock::now();
const int num_threads = 4;
std::vector threads;
for (int i = 0; i < num_threads; ++i) {
threads.push_back(std::thread(sort_array, my_array + i * array_size / num_threads, array_size / num_threads));
}
for (auto& th : threads) {
th.join();
}
auto end = std::chrono::system_clock::now();
auto elapsed_seconds = std::chrono::duration_cast(end – start).count();
“`
Now you have four threads that sort four sub-arrays simultaneously, and then you join them to get a sorted whole array. The elapsed time is less than the sequential sorting because the tasks are split up into several parts that run concurrently.
std::thread Methods: sleep, detach, joinable, this, and lambda
So far, we’ve covered the basics of std::thread, but it has more to offer, dawgs. Here are some methods that you can use to perform more advanced operations with std::thread:
– Sleep: Pauses the execution of a thread for a specified amount of time in milliseconds.
“`
std::this_thread::sleep_for(std::chrono::milliseconds(100));
“`
– Detach: Detaches a thread from the calling thread, allowing it to continue running independently.
“`
thread.detach();
“`
– Joinable: Returns true if the thread object is joinable; otherwise, it returns false.
“`
if (thread.joinable()) {
thread.join();
}
“`
– This: Returns the thread object’s ID.
“`
std::thread::id this_id = std::this_thread::get_id();
“`
– Lambda: You can also use lambda expressions to define the thread’s function.
“`
std::thread t([](){
std::cout << I'm running on a new thread! << std::endl;
});
t.join();
“`
Conclusion
So, dawgs, that’s all you need to know about std::thread and how to use it for your program’s multi-threading tasks. It’s a powerful tool that can help you to complete tasks faster by distributing them into smaller chunks and allowing them to run simultaneously. std::thread is easy to use and can be a useful addition to your programming toolkit.
Stay tuned for more gangster programming tips, dawgs!
