range based for loop temporary object lifetime issue example, C++ (clang)

range based for loop temporary object lifetime issue example

// range based for loop temporary object lifetime issue example
#include <iostream>

class TestRange
{
	bool _alive;
public:

TestRange() : _alive(true) {}
	~TestRange() { _alive = false; }

TestRange const &fluentAPIMethod() const { return *this; }
	TestRange const * begin() const { return this; }
	TestRange const * end() const { return this + 1; }

void checkAlive() const
	{
		if (_alive)
			std::cout << "OK  - DTOR not called yet\r\n";
		else
			std::cout << "ERR - DTOR already called on this\r\n";	//	this is an error
	}

};

int main()
{
#ifdef _MSC_FULL_VER
	std::cout << "MSVC  version " << _MSC_FULL_VER << " \r\n";
#elif defined (__clang__) && defined (__clang_major__) && defined (__clang_minor__) && defined (__clang_patchlevel__)
	std::cout << "CLANG  version " << __clang__ << "." << __clang_major__ << "." << __clang_minor__ << "." << __clang_patchlevel__  << " \r\n";
#elif defined (__GNUC__) && defined (__GNUC__) && defined (__GNUC_MINOR__)
	std::cout << "GCC   version " << __GNUC__ << "." << __GNUC_MINOR__ << "." << __GNUC_PATCHLEVEL__ << " \r\n";
#endif

for (auto & el : TestRange())
		el.checkAlive();

for (auto & el : TestRange().fluentAPIMethod())
		el.checkAlive();

return 0;
}


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