TITLE: New ruling on lifetime of temporaries

PROBLEM: walz@lamisun3.epfl.ch (Michael Walz)

I wonder how long is the lifetime of temporary objects created by
the compiler in C++.


RESPONSE: Viktor Yurkovsky <n4mation@panix.com>

According to the ARM, the lifetime of temporary objects is
implementation-dependent.  Therefore, you should not rely on the
existance of temporary objects beyond their normal function of
assignment.


RESPONSE: maxtal@physics.su.OZ.AU (John Max Skaller), Mon Jan 9

	Out of date. A temporary lasts to "end of full expression",
which is usually the end of the statement.


RESPONSE: fjh@munta.cs.mu.OZ.AU (Fergus Henderson), 8 Jan 95

Generally, they last until the end of their containing expression.
The exception is when they are used to initialize a reference, i.e.

	const T& r = temporary();

in which case the temporary's lifetime is the same as that of the reference.

Yes, that's true [the ARM saying its implementation dependent], but the
ANSI/ISO C++ committee changed the rules.
It is no longer implementation-dependant.  However, compilers are
still catching up, and so if you want to write portable code, you
should not depend on the new rules.

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