Re: [boost] Boost MSM parallel behavior with delayed self-transitions?

Subject: Re: [boost] Boost MSM parallel behavior with delayed self-transitions?
From: degski (degski_at_[hidden])
Date: 2017-03-22 14:59:09

On 21 March 2017 at 20:31, Danylo Malyuta via Boost <boost_at_[hidden]>
wrote:

> Here is sample code which attempts to replicate the diagram, but just for
> the A state (the B state is not included, which would be trivial to do):

Just for fun I coded up the simple approach (no dependencies other than
STL, no threads). Note that plenty of code/headers is/are dedicated to
printing the current time, which for some reason or another is crazy
complex for such a simple and common task.

#include <chrono>
#include <thread>

#include <iostream> // Just to print the current time...
#include <iomanip> // Just to print the current time...
#include <ctime> // Just to print the current time...

namespace sc = std::chrono;
typedef sc::high_resolution_clock hrc;

void a_action ( ) {

    std::time_t now_c = std::chrono::system_clock::to_time_t (
std::chrono::system_clock::now ( ) );
    std::cout << "Trying A again at " << std::put_time ( std::localtime ( &
now_c ), "%T" ) << "...\n";
}

void b_action ( ) {

    std::time_t now_c = std::chrono::system_clock::to_time_t (
std::chrono::system_clock::now ( ) );
    std::cout << "Trying B again at " << std::put_time ( std::localtime ( &
now_c ), "%T" ) << "...\n";
}

int main ( ) {

    sc::time_point < hrc > a_trigger = hrc::now ( ) + sc::seconds { 2 },
b_trigger = a_trigger + sc::seconds { 3 };

    std::time_t now_c = std::chrono::system_clock::to_time_t (
std::chrono::system_clock::now ( ) );
    std::cout << "Started at " << std::put_time ( std::localtime ( & now_c
), "%T" ) << '\n';

    while ( true ) {

        if ( a_trigger < b_trigger ) {

            std::this_thread::sleep_until ( a_trigger );
            a_action ( );
            a_trigger += sc::seconds { 2 };
        }

        else {

            std::this_thread::sleep_until ( b_trigger );
            b_action ( );
            b_trigger += sc::seconds { 5 };
        }
    }

    return 0;
}

Sample output:

Started at 08:56:34
Trying A again at 08:56:36...
Trying A again at 08:56:38...
Trying B again at 08:56:39...
Trying A again at 08:56:40...
Trying A again at 08:56:42...
Trying B again at 08:56:44...
Trying A again at 08:56:44...
Trying A again at 08:56:46...
Trying A again at 08:56:48...
Trying B again at 08:56:49...
Trying A again at 08:56:50...
Trying A again at 08:56:52...
Trying B again at 08:56:54...
Trying A again at 08:56:54...
Trying A again at 08:56:56...
Trying A again at 08:56:58...

degski