How to simulate inner exception in C++
- by Siva Chandran
Basically I want to simulate .NET Exception.InnerException in C++. I want to catch exception from bottom layer and wrap it with another exception and throw again to upper layer. The problem here is I don't know how to wrap the catched exception inside another exception.
struct base_exception : public std::exception
{
std::exception& InnerException;
base_exception() : InnerException(???) { } // <---- what to initialize with
base_exception(std::exception& innerException) : InnerException(innerException) { }
};
struct func1_exception : public base_exception
{
const char* what() const throw()
{
return "func1 exception";
}
};
struct func2_exception : public base_exception
{
const char* what() const throw()
{
return "func2 exception";
}
};
void func2()
{
throw func2_exception();
}
void func1()
{
try
{
func2();
}
catch(std::exception& e)
{
throw func2_exception(e); // <--- is this correct? will the temporary object will be alive?
}
}
int main(void)
{
try
{
func1();
}
catch(base_exception& e)
{
std::cout << "Got exception" << std::endl;
std::cout << e.what();
std::cout << "InnerException" << std::endl;
std::cout << e.InnerException.what(); // <---- how to make sure it has inner exception ?
}
}
In the above code listing I am not sure how to initialize the "InnerException" member when there is no inner exception. Also I am not sure whether the temporary object that is thrown from func1 will survive even after func2 throw?
