Migrating from Visual C++ 6 to C++.NET

[David++]

Hi,

I'm trying to compile a project in C++.Net which was built using Visual C++
6. I'm getting some major compile errors and need to find a solution soon. I
can either try and convert the project so it is compatible with .NET (which I
think will be error prone and risky) or I can downgrade to Visual C++ 6 and
build the project there. The problems I'm having are this -

1. I've tried using the recommended resolutions to Migrate my project and
they dont work.

2. I dont think it is possible to downgrade to Visual C++ 6 from Visual
C++.net as the downgrade page for this option leads to a dead page. Hopefully
this is possible however and someone will correct me.

Any views or tips appreciated,

Thanks,
David

[Carl Daniel [VC++ MVP]]

David++ wrote:

Hi,

I'm trying to compile a project in C++.Net which was built using
Visual C++
6. I'm getting some major compile errors and need to find a solution
soon. I can either try and convert the project so it is compatible
with .NET (which I think will be error prone and risky) or I can
downgrade to Visual C++ 6 and build the project there. The problems
I'm having are this -

1. I've tried using the recommended resolutions to Migrate my project
and they dont work.
Such as? Don't work how?

It'd help if you could post some representative code and the error messages
that you're getting.

Typical problems in porting code from VC6 include:

- Lack of the 'typename' keyword in places where the C++ standard (and
VC7.1+) require it.
- Dependency on the obsolete <iostream.h> version of I/O streams (use
<iostream> instead).
- Dependency on names being in the global namespace that are now (correctly)
in the ::std namespace.

In converting the project itself from VC6 to VC7 or later, the most common
problem is that of compilation options being converted improperly - in
particular, the project conversion has a nasty habit of turning all of your
VC6 per-project options into per-file options in the converted project,
which can be very confusing when you subsequently try to change project
options and find that nothing's changing in your build.

2. I dont think it is possible to downgrade to Visual C++ 6 from
Visual C++.net as the downgrade page for this option leads to a dead
page. Hopefully this is possible however and someone will correct me.

VS6 is still included in MSDN Professional and above, and is still available
for downgrade (although it's no longer supported).

-cd

[David++]

Hi Carl,

Thanks for the reply. I managed to sort the problems I was having. Someone
here in the office has VC++ 6 (which was unbeknowns to me until today) so I
just changed seats, compilation errors cleared right up. Thanks for all the
info you provided. This is very useful for future situations which might
arise.

Best Regards,

David Ross

"Carl Daniel [VC++ MVP]" wrote:

David++ wrote:

Hi,

I'm trying to compile a project in C++.Net which was built using
Visual C++
6. I'm getting some major compile errors and need to find a solution
soon. I can either try and convert the project so it is compatible
with .NET (which I think will be error prone and risky) or I can
downgrade to Visual C++ 6 and build the project there. The problems
I'm having are this -

1. I've tried using the recommended resolutions to Migrate my project
and they dont work.

Such as? Don't work how?

It'd help if you could post some representative code and the error messages
that you're getting.

Typical problems in porting code from VC6 include:

- Lack of the 'typename' keyword in places where the C++ standard (and
VC7.1+) require it.
- Dependency on the obsolete <iostream.h> version of I/O streams (use
<iostream> instead).
- Dependency on names being in the global namespace that are now (correctly)
in the ::std namespace.

In converting the project itself from VC6 to VC7 or later, the most common
problem is that of compilation options being converted improperly - in
particular, the project conversion has a nasty habit of turning all of your
VC6 per-project options into per-file options in the converted project,
which can be very confusing when you subsequently try to change project
options and find that nothing's changing in your build.

2. I dont think it is possible to downgrade to Visual C++ 6 from
Visual C++.net as the downgrade page for this option leads to a dead
page. Hopefully this is possible however and someone will correct me.

VS6 is still included in MSDN Professional and above, and is still available
for downgrade (although it's no longer supported).

-cd