exceptions.org

#+title: Exceptions
#+author: Nelson Rodrigues


C++ 17 exception and no-exception 

*Text and Source code:*
https://msdn.microsoft.com/en-us/library/4tebey8h.aspx


"...  When the catch statement is reached, all of the automatic variables that are in scope
between the throw and catch statements are destroyed in a process that is known as stack unwinding ..."

*Text and Source code:*
https://docs.microsoft.com/en-us/cpp/cpp/exceptions-and-stack-unwinding-in-cpp?view=vs-2017


"... Prior to C++17 there were two kinds of exception specification. The noexcept specification
was new in C++11. It specifies whether the set of potential exceptions that can escape the function
is empty. The dynamic exception specification, or throw(optional_type_list) specification, was deprecated
in C++11 and removed in C++17, except for throw(), which is an alias for noexcept(true). 
This exception specification was designed to provide summary information about what exceptions can be thrown 
out of a function, but in practice it was found to be problematic ..."

*Text and Source code:*
https://docs.microsoft.com/en-us/cpp/cpp/exception-specifications-throw-cpp?view=vs-2017


*noexcept*
-It turns an exception throw into a call to std::terminate().
-One can make a compile-time query if the function has been declared as noexcept.

*Text and Source code:*
https://akrzemi1.wordpress.com/2014/04/24/noexcept-what-for/


#+BEGIN_EXAMPLE C++

#include <iostream>
#include <functional>

using namespace std;

void test(int i) noexcept
{
	if(i == 0)
		throw 2.0;
	else
		cout << "i = " << i << endl;
}

int main()
{
	int * x = nullptr;
	try
	{
		test(10);
		test(0);
		
		x = new int();
		throw 20;
	}
	catch ( double e )
	{
		delete x;
		cout << "An exception (double) = " << e << endl;
	}
	catch ( int e )
	{
		delete x;
		cout << "An exception (int) = " << e << endl;
	}
	
	cout << "end";
	return 0;
}

#+END_EXAMPLE