Before trying out Niall's wealth of suggestions, just to fix up my own
erroneous example:
> From: Holger Joukl <holger.jo...@lbbw.de>
> A bit of a simplified example version using Boost's partial C++11
exception
> support
> would then be s.th. like:
>
> 0 $ cat dispatch_main_exception_map.cpp
> // File: dispatch_main_exception_map.cpp
>
> #include <iostream>
> [...]
> // this callback raises an exception, catches it and stores it in the
> // global (thread, exception)-map
> void guarded_callback_with_exception(cb_arg_t arg) {
> std::cout << "--> guarded exception-throwing CPP callback" << arg <<
> std::endl;
> try {
> throw std::runtime_error("throwing up");
> } catch (...) {
> std::cout << "storing exception in exception map" << std::endl;
> pthread_t current_thread = pthread_self();
> exception_map[current_thread] = boost::current_exception();
> exception_map.erase(current_thread);
> [...]
^^^^^^^^^^^^^^^^^^^
|
This defeats the purpose, of course, and rather needs to be put where the
re-throw takes place.
Shouldn't make late additions and then overlook the missing output.
$ cat dispatch_main_exception_map.cpp
// File: dispatch_main_exception_map.cpp
#include <iostream>
#include <exception>
#include <stdexcept>
#include <pthread.h>
// header-only:
#include <boost/unordered_map.hpp>
// header-only:
#include <boost/exception_ptr.hpp>
#include "dispatch.h"
// the global per-thread exception storage
boost::unordered_map<pthread_t, boost::exception_ptr> exception_map;
void callback(cb_arg_t arg) {
std::cout << "--> CPP callback" << arg << std::endl;
std::cout << "<-- CPP callback" << arg << std::endl;
}
// this callback raises an exception
void callback_with_exception(cb_arg_t arg) {
std::cout << "--> exception-throwing CPP callback" << arg << std::endl;
throw std::runtime_error("throwing up");
std::cout << "<-- exception-throwing CPP callback" << arg << std::endl;
}
// this callback raises an exception, catches it and stores it in the
// global (thread, exception)-map
void guarded_callback_with_exception(cb_arg_t arg) {
std::cout << "--> guarded exception-throwing CPP callback" << arg <<
std::endl;
try {
throw std::runtime_error("throwing up");
} catch (...) {
std::cout << "storing exception in exception map" << std::endl;
pthread_t current_thread = pthread_self();
exception_map[current_thread] = boost::current_exception();
}
std::cout << "<-- guarded exception-throwing CPP callback" << arg <<
std::endl;
}
int main(void) {
std::cout << "--> CPP main" << std::endl;
cb_arg_t s = "CPP main callback argument";
std::cout << std::endl;
invoke(&callback, s);
std::cout << std::endl;
invoke(&guarded_callback_with_exception, s);
pthread_t current_thread = pthread_self();
if (exception_map.find(current_thread) != exception_map.end()) {
try {
std::cout << "rethrowing exception from exception map" <<
std::endl;
boost::exception_ptr current_exception(exception_map
[current_thread]);
exception_map.erase(current_thread);
boost::rethrow_exception(current_exception);
} catch (const std::exception& exc) {
std::cout << "caught callback exception: " << exc.what() <<
std::endl;
}
}
std::cout << std::endl;
try {
invoke(&callback_with_exception, s);
} catch (const std::exception& exc) {
std::cout << "caught callback exception: " << exc.what() <<
std::endl;
}
std::cout << std::endl;
std::cout << "<-- CPP main" << std::endl;
return 0;
}
0 $ ./a.out
--> CPP main
--> invoke(136888, CPP main callback argument)
--> CPP callbackCPP main callback argument
<-- CPP callbackCPP main callback argument
<-- invoke(136888, CPP main callback argument)
--> invoke(137608, CPP main callback argument)
--> guarded exception-throwing CPP callbackCPP main callback argument
storing exception in exception map
<-- guarded exception-throwing CPP callbackCPP main callback argument
<-- invoke(137608, CPP main callback argument)
rethrowing exception from exception map
caught callback exception: throwing up
--> invoke(137112, CPP main callback argument)
--> exception-throwing CPP callbackCPP main callback argument
caught callback exception: throwing up
<-- CPP main
Holger
Landesbank Baden-Wuerttemberg
Anstalt des oeffentlichen Rechts
Hauptsitze: Stuttgart, Karlsruhe, Mannheim, Mainz
HRA 12704
Amtsgericht Stuttgart
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