[gnu.g++] g++/CFront 2.0 Source Compatibility?

Chewy@cup.portal.com (Paul Frederick Snively) (08/09/90)

Hi, y'all!

I'm sure this is a rather stupid question, but I need to know...

To what extent are AT&T CFront 2.0 and g++ source-code compatible?

The question, of course, is whether a forthcoming project can be done in g++
using existing documentation, such as the Lippman (sp?) text, without running
into headaches.

Issues such as whether g++ and AT&T CFront construct virtual tables the same
way, etc. are irrelevant.

Any insights are appreciated.

Thanks!

Chewy@cup.portal.com

keith@csli.Stanford.EDU (Keith Nishihara) (08/09/90)

In <32603@cup.portal.com> Chewy@cup.portal.com (Paul Frederick Snively) writes:

>Hi, y'all!

>I'm sure this is a rather stupid question, but I need to know...

>To what extent are AT&T CFront 2.0 and g++ source-code compatible?

It is generally a good idea to look before you leap.  I can't believe
you site expires articles so fast that the following four were not
available when you posted your question:
	a Jim D 5 11-Y-03  14  porting tips for c++
	b Jim ADCOCK       10  >
	c George Wu       118  >
	d Keith Nishihara  79  >>
The article by George Wu and my followup (as Keith Nishihara) address
your question.

In summary, g++ and cfront 2.0 are so similar that  with  reason-
able  care you should have no problem.  I recently ported a 35000
line application written under g++ on a DecStation to cfront on a
Sun.   Total  time was 10 hours, and most of that was recoding to
fix an incompatibility in the event ordering between the X window
implementations  on  the  two  machines.  My advice is to try the
port when you have about 5 to 10 k lines of code, learn  the  in-
compatibilities,  and  then you will have no problem.  My impres-
sion is that g++ is a more faithful implementation of the implied
standard  (with  extensions  discussed in the gnu documentation),
however, that is probably because I hit all the problems  in  the
cfront implementation at once.

Neil/.		Neil%teleos.com@ai.sri.com

bashford@scripps.edu (Don Bashford) (08/10/90)

In article <14826@csli.Stanford.EDU> Neil Hunt <Neil%teleos.com@ai.sri.com> writes:
>In <32603@cup.portal.com> Chewy@cup.portal.com (Paul Frederick Snively) writes:
>
>>Hi, y'all!
>>I'm sure this is a rather stupid question, but I need to know...
>>To what extent are AT&T CFront 2.0 and g++ source-code compatible?
>
>It is generally a good idea to look before you leap.  I can't believe
>you site expires articles so fast that the following four were not
>available when you posted your question:
>	a Jim D 5 11-Y-03  14  porting tips for c++
>	b Jim ADCOCK       10  >
>	c George Wu       118  >
>	d Keith Nishihara  79  >>

I don't know about him, but on *our* machine they are expired.
Could someone e-mail them to me?

I'm also interested in the question of libg++ portability.
I recently tried to give my code (including the necessary libg++-include 
files and genclass generated code) away to someone who has only
a cfront clone and it could not deal with libg++'s use of GNU
extensions such as the use of named return values in String.h.

So my questions are:
1) Is there a cfront-compatable version of libg++ available,
   or better yet, a program to convert g++ extended code into
   standard c++ (alright maybe I'm dreaming).
2) How hard is it really to get libg++ stuff to compile under cfront

I'm not in a position to explore this on my own, since g++ is the
only c++ I've got (and I think its great!).

Donald Bashford
bashford@scripps.edu