Path: utzoo!attcan!uunet!cs.utexas.edu!rutgers!columbia!read.columbia.edu!kearns
From: kearns@read.columbia.edu (Steve Kearns)
Newsgroups: comp.lang.c++
Subject: lifetime of temporary objects
Message-ID: <6374@columbia.edu>
Date: 24 Jun 89 22:12:42 GMT
Sender: news@columbia.edu
Reply-To: kearns@read.UUCP ()
Organization: Columbia University Department of Computer Science
Lines: 27


On pg. 43 of the "bible" it says:
"an object is created when its definition is encountered and 
 destroyed when its name goes out of scope."

What about temporary variables:  for example,
with the following declarations...

struct foo {int * dummy...};
foo foo::make();
int bar(int);

... is the lifetime of the temporary "foo" returned by foo (below)
guaranteed not to be destructed until after bar returns?  

bar(make().dummy);

This can be important when doing reference counting.
The above code is more efficient than the alternative:

// define bar to take a ref instead
int bar(foo& )
// call bar this way
bar(make());

-steve
(kearns@cs.columbia.edu)