Let's say that I have a simple D program as follows:

void main() {
  while(true) {
  }
  assert(false);
}

It will run until killed. It also uses a lot of CPU. Is there a good DLang way to make it use less CPU?

Selim

On Saturday, 25 September 2021 at 09:35:16 UTC, Selim Ozel wrote:

void main() {
  while(true) {
  }
  assert(false);
}

void main() {
    import core.sys.posix.unistd : pause;

    while (true) {
        pause;
    }
    assert(false);
}

man 2 pause, it sleeps the calling thread until a signal is received.

On Saturday, 25 September 2021 at 09:46:09 UTC, jfondren wrote:

void main() {
  while(true) {
  }
  assert(false);
}

void main() {
    import core.sys.posix.unistd : pause;

    while (true) {
        pause;
    }
    assert(false);
}

Thanks for the answer. I have actually just re-remembered the thread library in D. Following worked for me.

import core.thread;
import core.time: dur;
import std.stdio;

void threadFunc(){
  writeln("Thread entered");
  while(true){
    Thread.sleep( dur!("seconds")( 5 ) );
    writeln("Once per 5 seconds.");
  }
}

void main() {
  auto composed = new Thread(&threadFunc).start();
}

On Saturday, 25 September 2021 at 10:17:32 UTC, Selim Ozel wrote:

import core.thread;
import core.time: dur;
import std.stdio;

void threadFunc(){
  writeln("Thread entered");
  while(true){
    Thread.sleep( dur!("seconds")( 5 ) );
    writeln("Once per 5 seconds.");
  }
}

void main() {
  auto composed = new Thread(&threadFunc).start();
}

What this program does is run with two threads, one sleeping in a loop and one waiting for the other thread to end. If you're starting a thread so that you can call Thread.sleep in it, that's not necessary. You could just rename threadFunc to main here, and of course get rid of the original main(), and it'd work.

On Saturday, 25 September 2021 at 10:32:10 UTC, jfondren wrote:

import core.thread;
import core.time: dur;
import std.stdio;

void threadFunc(){
  writeln("Thread entered");
  while(true){
    Thread.sleep( dur!("seconds")( 5 ) );
    writeln("Once per 5 seconds.");
  }
}

void main() {
  auto composed = new Thread(&threadFunc).start();
}

That's much better. Thanks a lot.

Selim

On Saturday, 25 September 2021 at 10:37:25 UTC, Selim Ozel wrote:

Just a reminder, you can also write 5.seconds

On Sunday, 26 September 2021 at 08:50:47 UTC, Imperatorn wrote:

The final program is.

import core.thread;

void main() {
  while(true) {
    Thread.sleep(5.seconds);
  }
}