Interrupt C++ function from Python (place pybind11 into the same folder, then compile using cmake . && cmake --build .)

A.cpp

#include "A.hpp"

A::A(int a_init)

    : a(a_init),
      interrupted(false)
{

}

A::~A(){

}

void A::solve(){
 
    while (!interrupted) {

        std::this_thread::sleep_for(std::chrono::milliseconds(1000));
        
        if (!interrupted) {
            
            py::print(++a);
        }
    }

    if (interrupted) {

        std::cout << "Interrupted.\n";
    }
}

void A::stop() {

    std::cout << "Interrupting ... \n";

    interrupted = true;
    
}

A.hpp

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

#include <pybind11/pybind11.h>
#include <pybind11/stl.h>

namespace py = pybind11;

class A {

public:
    A(int a_init);
    ~A();
    void solve();
    void stop();
    
    std::atomic<bool> interrupted;

private:

    int a;

};

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.12)
project(a)

# Set source directory
set(SOURCE_DIR ".")

# Tell CMake that headers are also in SOURCE_DIR
include_directories(${SOURCE_DIR})
file(GLOB SOURCES ${SOURCE_DIR}/*.cpp)
set(${SOURCES})

# Generate Python module
add_subdirectory(pybind11)
pybind11_add_module(_a ${SOURCES} "${SOURCE_DIR}/PythonBindings.cpp")

if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE Release)
endif()

set(CMAKE_CXX_FLAGS "-O3 -Wpedantic -Wextra")

PythonBindings.cpp

#include "A.hpp"

PYBIND11_MODULE(_a, m)
{
    py::class_<A>(m, "A")
        .def(py::init<int>())
        .def("solve", &A::solve)
        .def("stop", &A::stop);
}

test.py

import signal
import threading

from _a import A
a = A(3)

def handle_interrupt(signum, frame):
    
    if signum == signal.SIGINT:
    
        a.stop()

signal.signal(signal.SIGINT, handle_interrupt)

a.solve()