Initializing objects on the heap

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2 total messages Started by sher Thu, 01 May 1986 01:34

#177

Author: sher
Date: Thu, 01 May 1986 01:34

23 lines
1421 bytes

Right now I am writing in c++ a program to manipulate a linked list.

This means that proceedures and function often want to create objects
on the heap since it is a bad idea to return objects on the stack.
Also it is a good idea to initialize all objects you create.

The only way I know to put an initialized object onto the heap is:

foo * fp = new foo;
foo f ( init );
*fp = init;

If f is a large object with many pieces this is a very wasteful proceedure
since this involves copying f into the space of fp after going to the
work of creating and allocating f.  Is there a better way of doing
this?  I know it can be done by creating a function that takes
fp and initializes it with init but I find this inelegant.  Why have
constructors if they have to always be bypassed?

-- 
-David Sher
sher@rochester
seismo!rochester!sher

BSD porting problems

#180

Author: oneill
Date: Thu, 01 May 1986 23:20

34 lines
1310 bytes

We are trying to port the c++ compiler to our BSD site and have run up
against a problem in using 'cout <<'.  Namely, any program we put it in 
bombs out as in the example below.  Any ideas?


The program:

	% more hello.c
	#include <stream.h>
	
	main() {
		cout << "123Hello\n";
	}
	
The error:

	% hello
	Bus error (core dumped)
	
The debug:

	% dbx hello
	dbx version 5 of 7/31/84 17:27 (tisstyx).
	Type 'help' for help.
	warning: core dump ignored
	reading symbolic information ...
	(dbx) run
	
	bus error in _ostream__lshiftFPC__ at line 471 in file "out..c"
	  471   ) ) ) == -1) 
	(dbx) where
	_ostream__lshiftFPC__(_auto_this = 0x22ec, _auto_s = "23Hello\n"), line 471 in "out..c"
	main(0x1, 0x7fffee9c, 0x7fffeea4), line 4 in "hello.c"
	(dbx) q

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