Path: utzoo!telly!ddsw1!mcdchg!rutgers!ukma!tut.cis.ohio-state.edu!cs.utexas.edu!sm.unisys.com!ucla-cs!casey
From: casey@CS.UCLA.EDU
Newsgroups: gnu.g++.bug
Subject: GNU C++ 1.27 does not call destructors for temporaries
Keywords: compiler temporaries, constructors, destructors
Message-ID: <16551@shemp.CS.UCLA.EDU>
Date: 6 Oct 88 00:21:43 GMT
Sender: news@CS.UCLA.EDU
Reply-To: casey@CS.UCLA.EDU (Casey Leedom)
Distribution: gnu
Organization: UCLA
Lines: 73


VERSION:
	GNU CC 1.27
	GNU C++ 1.27
	GNU LIBG++ 1.25

CLIENT MACHINE:
	VAX 8350

CLIENT OPERATING SYSTEM:
	ULTRIX 2.2 - no patches installed

SYNOPSIS:
	The GNU C++ compiler automatically allocates temporaries for
	expression evaluation.  It properly calls constructors for the
	class of the temporaries, but doesn't call destructors for
	them.

REPEAT-BY:
	The following program demonstrates the problem.  No fix yet,
	but we'll start looking immediately because we can't proceed
	with our work until this is fixed.  If anyone comes up with
	a fix please mail us a copy.  Thanks!

-----
char *malloc(unsigned int);

/*
 * CLASS FOO
 */
class foo {
	int *store;
public:
	foo(int);
	~foo(void);
	friend foo operator+(foo &, foo&);
};

inline foo::foo(int n)			/* FOO CONSTRUCTOR */
{
	puts("foo constructor");
	store = (int *)malloc(sizeof(*store));
	if (store)
		*store = n;
	else
		perror("malloc");
}

inline foo::~foo(void)			/* FOO DESTRUCTOR */
{
	puts("foo destructor");
	if (store)
		free(store);
}

inline foo operator+(foo &a, foo &b)	/* FOO OPERATOR + */
{
	return(*a.store + *b.store);
}


/*
 * Trivial main program.
 *
 * GNU C++ generates a temporary of type foo to handle the expression to
 * compute the value of s.  A constructor for the temporary is properly
 * called, but a destructor for it is never called.  This is a bug.
 */
main()
{
	foo a(1), b(2), c(5);
	foo s = a + b + c;
}