NetNews Usenet Archive 1992 #19/NN_1992_19.iso/spool/comp/lang/cplus/13040

Text File | 1992-08-29 | 1.6 KB | 47 lines

Newsgroups: comp.lang.c++
Path: sparky!uunet!uunet.ca!frumious!pat
From: [e-mail] (Patrick Smith)
Subject: Re: Garbage Collection for C++
Message-ID: <[e-mail]>
Date: Sat, 29 Aug 1992 05:41:13 GMT
Reply-To: uunet.ca!frumious!pat
References: <[e-mail]> <[e-mail]> <[e-mail]>
Organization: None
Lines: 35

[e-mail] (Dave Gillespie) writes:
|Every third posting in the destruction-of-temporaries thread
|in this group ends with "if only we had GC so we could solve this
|problem once and for all..."

Actually, I don't think adding GC to C++ would solve the problem
of when to destroy temporaries.

GC could help with cases such as this:

   String s, t;
   const char* p = (const char*) (s + t);
   // ... do something with p

but I don't see how it would help with this:

   ofstream("some_file") << "Hello, " << "world!\n";

Well, there is one way.  One could require that all temporaries be
allocated and destroyed by the garbage collection mechanism.
There are at least two problems with this:

1) The destructors for the temporaries are run arbitrarily late,
   if indeed they are ever run (this depends on the rules GC is
   subject to).  In the above example, the programmer probably
   wanted the ofstream destructor to be run fairly soon.

2) Some (most? almost all?) applications would run more slowly if
   temporaries were allocated from a garbage-collected heap instead
   of from the stack.

--
Patrick Smith
uunet.ca!frumious!pat
[e-mail]