When to add __gc decorator

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hey everyone,

If I am writing a .NET library using managed C++, when exactly do I have to
decorate a pointer with the __gc decorator?

Thanks,
 
TT (Tom Tempelaere) said:
If I am writing a .NET library using managed C++, when exactly do I have
to
decorate a pointer with the __gc decorator?
Click to expand...

Well, pointers to managed objects are always __gc. So mostly, you don't have
to be explicit where you point to managed objects though it doesn't hurt.

Suppose though, that you have a managed class and that that managed class
has a member which has an unmanaged type - say integer. If you needed a
pointer to that integer then you'd need to mark the pointer as __gc. That's
because that ordinary integer is set on the managed heap and it can move out
from under you.

I hope this helps. I had hoped to come up with a more definitive, less
annecdotal explanation for you. I scanned the book "Essential Guide to
Managed Extensions for C++" hoping to find some advice from on high that I
could quote. What there is in the book is a whole _chapter_ on the topic.
I'd recommend the book, but depending on your release schedule, you might
want to wait for a book on C++/CLI which supplants MC++ in VS.Net 2005

Regards,
Will
 
you may need to use __gc on managed arrays, too.

i'd also recommend the same thing; wait for C++/CLI. you can get its
beta1 or latest ctp and enjoy using new language. there is no __gc in
C++/CLI.
 
.... depending on your release schedule, you might
want to wait for a book on C++/CLI which supplants MC++ in VS.Net 2005

Regards,
Will
Click to expand...

I had just posted a query about books on C++/CLI. Looks like you just
answered it. I'm surprised that no one got the jump on the 2005
compiler release.

Well, in the absence of a book, are there any good web-based
references on the subject?
 
_B said:
On Tue, 8 Mar 2005 11:03:51 -0500, "William DePalo [MVP VC++]"
I had just posted a query about books on C++/CLI. Looks like you just
answered it. I'm surprised that no one got the jump on the 2005
compiler release.

Well, in the absence of a book, are there any good web-based
references on the subject?
Click to expand...

This is an introduction:

http://msdn.microsoft.com/msdnmag/issues/05/02/PureC/default.aspx

This details the differences between MC++ and C++/CLI:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnvs05/html/TransGuide.asp

They should get you started. You can try googling for more, perhaps
searching for articles written by Lippman or ones on "C++/CLI"

Regards,
Will
 
Back
Top