Receive async exception directly - c++

Question

class ClassA
{
void running()
{
int count = 0;
m_worker_stop.store(true);
while (m_worker_stop.load() == false)
{
count++;
if (count == 10)
{
// Make exception
std::vector v(100000000000);
}
}
}
void start()
{
m_worker = std::async(std::launch::async, &ClassA::running, this);
}
void stop()
{
m_worker_stop.store(true);
if (m_worker.valid())
m_worker.get(); // catch exception in this point
}
std::future<void> m_worker;
std::atomic_bool m_worker_stop = { false };
}
class Main // this is single-ton Main class
{
...
void running()
{
try {
m_classA->start();
// Wait for external signal(ex. SIGINT, SIGTERM, ..)
while (true) { // signal check }
m_classA->stop();
}
catch(std::exception& e) {
// re-create throwed object
}
catch(...) {
// re-create throwed object
}
}
}
int main()
{
Manager::getInstance()::running();
return 0;
}
Hello, everyone.
The approximate structure of the program is as above.
In fact, I have not only classA but also many other objects such as B, C, and D.
(start() and stop() function is simillar !)
An exception was raised using std::vector v(1000000..)
However, it became a catch when stop() was activated.
What I actually want is to delete the classA object and re-create it if an exception occurs.
So I need to catch directly when exception was occured.
In this case, is any idea to get exception without wait for signals?

Answer 1

Here is one way of achieving the effect you want:
class Main // this is single-ton Main class
{
...
void running()
{
for (size_t i = 0; i < max_tries; ++i)
{
try {
m_classA->start();
// Wait for external signal(ex. SIGINT, SIGTERM, ..)
while (true) {
// signal check ...
}
m_classA->stop();
// path to happy ending :)
LOG("Main::running(): Operation successful.",
return;
}
catch(std::exception& e) {
LOG("Main::running(): Exception caught: message:\"{}\"", e.what());
}
catch(...) {
LOG("Main::running(): Unspecified exception caught, aborting.");
return; // Example of 'unrecoverable error'
}
// this part is only executed after an exception.
m_classA->shut_down(); // if you need some special shut down after an error.
m_classA.clear(); // this is redundant, but explicit (optional)
m_classA = MakeMeAnA(); // call our favorite A construction method.
}
// path to total failure :(
LOG("Main::running(): Exiting after {} failed attempts", max_tries);
}
private:
static constexpr size_t max_tries = 3;
};