c task with cancellation token example:A Comprehensive Guide to Tasks with Cancellation Tokens in C

A Comprehensive Guide to Tasks with Cancellation Tokens in C

C is a versatile programming language that is widely used for various tasks, including task parallelism. Cancellation tokens are a powerful feature in C that allow developers to cancel tasks in progress, which is particularly useful in task parallelism. This article provides a comprehensive guide to tasks with cancellation tokens in C, explaining the concepts, syntax, and examples.

Cancellation Tokens

Cancellation tokens are used to indicate that a task should be canceled. They are issued by a cancellation manager, which is responsible for managing the cancellation tokens. When a task receives a cancellation token, it can use it to cancel itself or other tasks. Tasks that have received a cancellation token will automatically cancel if the token is canceled by the cancellation manager.

Task Parallelism

Task parallelism is the execution of tasks in parallel, using multiple cores or processors. This allows for faster execution and improved performance in complex tasks. Cancellation tokens are a key component in task parallelism, as they allow developers to cancel tasks in progress if necessary.

Cancellation Tokens in C

Cancellation tokens in C are implemented using the `std::token_callback` template class, which provides a callback function that is called when a cancellation token is canceled. The `std::token_callback` class also provides a `std::cancel_token` object that can be used to cancel cancellation tokens.

Example: A Task with a Cancellation Token

The following example demonstrates a task with a cancellation token in C.

```c

#include

#include

#include

#include

typedef struct {

int value;

std::cancel_token cancel_token;

} MyTask;

static void my_task_runner(const MyTask& task, const std::cancel_token& ct) {

for (int i = 0; i tasks(tasks_count);

std::vector values(values_count);

for (int i = 0; i threads;

for (int i = 0; i < tasks_count; ++i) {

threads.push_back(std::thread(my_task_runner, std::ref(tasks), cancel_token));

}

std::cout << "Threads count: " << threads.size() << std::endl;

std::this_thread::sleep_for(std::chrono::seconds(10));

cancel_token.cancel();

for (std::thread& thread : threads) {

thread.join();

}

std::cout << "Task results: " << std::endl;

for (int i = 0; i < tasks_count; ++i) {

std::cout << "Task " << i << " result: " << tasks.value << std::endl;

}

return 0;

}

```

Cancellation tokens are a powerful feature in C that allow developers to cancel tasks in progress. This article provided a comprehensive guide to tasks with cancellation tokens in C, including the concepts, syntax, and example. By understanding and using cancellation tokens, developers can create more efficient and scalable applications using task parallelism.