How to port to GNUstep ?

[Richard van Paasen]

Hi,


I'm porting an application (over 200.000 LOC) from NeXTSTEP
(release 3.3) to GNUstep, on Linux. Since this is a large
application, and my first NeXTSTEP porting job, I'd like to
have comments from you.

1.
I've read that it is advised to port via OpenStep 4.2. Is it
advised to get the app completely running on OpenStep or will
it suffice to use OpenStep 4.2 for only the tools it provides
for the porting job? E.g. the application contains .nib files,
which will have to be converted on a Mac right? But how about
code that uses NX calls for which GNUstep provides alternative
NS calls? Should this code also be ported to OpenStep first?

2.
Leads me to the second question. What can I exactly expect from
OpenStep? What tools does it offer to port from NeXTSTEP? Does
OpenStep (Mac OS X) implement all functionality of NeXTSTEP?
I missed some stuff in GNUstep, e.g. NXPtrStructKeyPrototype and
NXStream. Will I have to fix much by hand?

3.
What will have to be done to port (parts of) the application from
OpenSTEP to GNUstep? Will it run out of the box or do I have to
fix things first?  Which tools are available?

4.
Are there applications which have been successfully ported from
NeXTSTEP? And applications that could not be ported? I am looking
for experiences of other people.

5.
How can you tell when it will be easy/hard to port an application
from NeXTSTEP to GNUstep?


- Richard van Paasen.