CODEWITHSUNDEEP
c++multithreading
hexeditor
hexeditor

Reputation: 174

How to run method/function on a separate thread in c++

I am a beginner in C++, so I don't know much.

Here is a function I have:

void example() {
     for(int i = 0; i < 5; i++) {
          // do stuff
     }
}

If I call this function, it will wait for it to be finished before continuing:

int main() {
     example();

     otherThingsGoHere();
     otherThingsGoHere();
     otherThingsGoHere();

     return 0;
}

The otherThingsGoHere() doesn't get called until example() is done.

My goal is to have that function be able to loop 60/70 fps in a loop forever.

And I did get it working, except nothing below that will happen since it is in an infinite loop.

I've been a C# developer for some time and I know that in c#, you can use async functions to run on a separate thread. How do I implement something like this in C++?

Edit: I am not asking for you to put the otherThingsGoHere in front of the main because the other things is going to be another loop, so I need both of them to run at the same time

Upvotes: 3

Views: 8547

Answers (1)

wohlstad
wohlstad

Reputation: 28074

You can use a std::thread and run the example() function from that new thread.

A std::thread can be started when constructed with a function to run. It will run potentially in parallel to the main thread running the otherThingsGoHere. I wrote potentially because it depends on your system and number of cores. If you have a PC with multiple cores it can actually run like that. Before main() exits it should wait for the other thread to end gracefully, by calling std::thread::join().

A minimal example for your case would be:

#include <thread>
#include <iostream>
#include <chrono>

void example() {
    for (int i = 0; i < 5; i++) {
        std::cout << "thread...\n";
        std::this_thread::sleep_for(std::chrono::milliseconds(100));
    }
}

void otherThingsGoHere() {
    std::cout << "do other things ...\n";
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
}

int main() {
    std::thread t{ example };

    otherThingsGoHere();
    otherThingsGoHere();
    otherThingsGoHere();

    t.join();
    return 0;
}

Upvotes: 4

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