Are Handles ever recycled within the same drawing?

[jcheard]

See subject.  

[arcticad · Accepted solution]

http://forums.autodesk.com/t5/Autodesk-ObjectARX/Handles-are-they-ever-reused-within-a-drawing/td-p/...

[jcheard]

Wow--shame on me for not even searching.

So theoretically, it seems that then there is a point at which AutoCAD will crash if a single drawing is modified and saved enough.  Is this assertion true?

[arcticad]

Not that I was aware of. Who said this?

[jcheard]

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@arcticad wrote:

Not that I was aware of. Who said this?

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Well, if Handles are never recycled--then theoretically a drawing could have consisted of so many objects (regardless of whether or not most have been erased and purged) that all of the handles could be used... given that there would have had to be roughly 2^64 objects.

[jeff]

Looks like time to code a loop and store a counter and/ or Database.Handseed value and see what happens.

[arcticad]

Well, We would have to ask Autodesk what that limit is.

The Handle header is a 32 bits so we can guess that it holds

4,294,967,295 objects. but this is a guess. 

http://www.opendesign.com/files/guestdownloads/OpenDesign_Specification_for_.dwg_files.pdf

[jcheard]

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@arcticad wrote:

Well, We would have to ask Autodesk what that limit is.

The Handle header is a 32 bits so we can guess that it holds

4,294,967,295 objects. but this is a guess. 

http://www.opendesign.com/files/guestdownloads/OpenDesign_Specification_for_.dwg_files.pdf

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32bits eh?  AutoCAD 2011 Documentation says 64bit

Description

This .NET class wraps the AcDbHandle ObjectARX class.

The Handle class is the ObjectARX class designed to encapsulate the 64-bit integer handle identifiers that have been in AutoCAD for several releases before R13. A handle uniquely identifies an DBObject within a single database and is saved with that object in the database so that it persists from session to session. Handles are not unique across databases, however. In fact, duplication across databases is almost a certainty, since all databases start with the same hand seed value of 1 and go up from there.

[jeff]

Definition for Database.Handseed Property

Accesses the current HANDSEED value for the database. The HANDSEED is a counter which maintains the next available handle number. Handles are 64-bit integers represented in DXF and LISP/ADS in hexadecimal form as a string. In hexadecimal, a 64-bit integer can be up to 16 digits.