source: doc/theses/andrew_beach_MMath/code/cond-catch.cpp@ cb6b8cb

// Conditional Match (or Re-Raise)
#include <chrono>
#include <cstdlib>
#include <exception>
#include <iostream>

using namespace std::chrono;

struct EmptyException : public std::exception {};

bool should_catch = false;

void throw_exception() {
        throw EmptyException();
}

void cond_catch() {
        try {
                throw_exception();
        } catch (EmptyException & exc) {
                if (!should_catch) {
                        throw;
                }
                asm volatile ("# catch block (conditional)");
        }
}

int main(int argc, char * argv[]) {
        unsigned int times = 1;
        if (1 < argc) {
                times = strtol(argv[1], nullptr, 10);
        }
        if (2 < argc) {
                should_catch = strtol(argv[2], nullptr, 10);
        }

        time_point<steady_clock> start_time = steady_clock::now();
    for (unsigned int count = 0 ; count < times ; ++count) {
        try {
                        cond_catch();
                } catch (EmptyException &) {
                        asm volatile ("# catch block (unconditional)");
                }
    }
        time_point<steady_clock> end_time = steady_clock::now();
        nanoseconds duration = duration_cast<nanoseconds>(end_time - start_time);
        std::cout << "Run-Time (ns): " << duration.count() << std::endl;
}