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US5398334A
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System for automatic garbage collection using strong and weak encapsulated pointers
Assignee: General Electric Co
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Filing: 1992-04-06
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Granted: 1995-03-14
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Expires: 2012-04-06
Abstract
Abstract The present invention solves both the dangling pointer problem and the garbage collection problem in software systems. Safe object pointers are divided into strong and weak pointers. Strong pointers point to an object unless they are explicitly assigned a new value, set to null, or destroyed. Weak pointers point to an object as long as the object has not been destroyed. If an object is destroyed, the weak pointer effectively becomes null, thus allowing the breaking up of cycles of references in a computer memory.
Inventors
- 👤 Terry M. Topka
- 👤 Paul C. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:30
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/0223; G06F12/023; G06F12/0253; G06F12/0261; G06F16/00; G06F16/20; G06F16/28; G06F16/289; Y; Y10; Y10S; Y10S707/00; Y10S707/99951; Y10S707/99956; Y10S707/99957
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
173 words
A method for automatic garbage collection in a software system comprising the steps of: using strong pointers belonging to an application being run on said software system to reference objects therein, said objects maintaining a reference count of each strong pointer pointing thereto; identifying cycles of strong pointers to objects in said software system; replacing at least one of the strong pointers to said objects in said identified cycles with a volatile weak encapsulated pointer belonging to the application being run on said software system, said objects maintaining a separate reference count for each volatile weak pointer pointing thereto, said objects decreasing the strong pointer reference count as a volatile weak pointer is replaced for a strong pointer; destroying any object as the strong pointer count reaches zero or as the volatile weak reference count reaches zero if and only if the strong pointer count is zero; and determining whether said objects in said identified cycles are safely referenced, said objects being safely referenced if the strong reference count is greater than zero.
Claim 2
Independent Claim
173 words
A method for automatic garbage collection in a software system comprising the steps of: using strong pointers belonging to an application being run on said software system to reference objects therein, said objects maintaining a reference count of each strong pointer pointing thereto; identifying cycles of strong pointers to objects in said software system; replacing at least one of the strong pointers to said objects in said identified cycles with a volatile weak encapsulated pointer belonging to the application being run on said software system, said objects maintaining a separate reference count for each volatile weak pointer pointing thereto, said objects decreasing the strong pointer reference count as a volatile weak pointer is replaced for a strong pointer; destroying any object as the strong pointer count reaches zero or as the volatile weak reference count reaches zero if and only if the strong pointer count is zero; and determining whether said objects in said identified cycles are safely referenced, said objects being safely referenced if the strong reference count is greater than zero.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-03-13 | 1998-09-12 | 1999-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-13 | 2002-09-12 | 2003-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-13 | 2006-09-12 | 2007-03-14 | $7700.00 | Window Closed / Lapsed |