Search results
Results from the WOW.Com Content Network
Stop-and-copy garbage collection in a Lisp architecture: [1] Memory is divided into working and free memory; new objects are allocated in the former. When it is full (depicted), garbage collection is performed: All data structures still in use are located by pointer tracing and copied into consecutive locations in free memory.
Some contexts allow for deterministic destruction, but some do not. Notably, in a garbage-collection environment, objects are destroyed when the garbage collector chooses. The syntax for creation and destruction varies by programming context. In many contexts, including C++, C# and Java, an object is created via special syntax like new typename().
Garbage collection uses various algorithms to automatically analyze the state of a program, identify garbage, and deallocate it without intervention by the programmer. Many modern programming languages such as Java and Haskell provide automated garbage collection.
A resurrected object may be treated the same as other objects, or may be treated specially. In many languages, notably C#, Java, and Python (from Python 3.4), objects are only finalized once, to avoid the possibility of an object being repeatedly resurrected or even being indestructible; in C# objects with finalizers by default are only finalized once, but can be re-registered for finalization.
In computer programming, tracing garbage collection is a form of automatic memory management that consists of determining which objects should be deallocated ("garbage collected") by tracing which objects are reachable by a chain of references from certain "root" objects, and considering the rest as "garbage" and collecting them.
Also, most garbage collectors scan "live" object references, and not the memory that these objects use for their content. This means that any number of "dead" objects without references can be discarded with little cost. In contrast, keeping a large number of "live" but unused objects increases the duration of garbage collection. [1]
In computer science, a mark–compact algorithm is a type of garbage collection algorithm used to reclaim unreachable memory. Mark–compact algorithms can be regarded as a combination of the mark–sweep algorithm and Cheney's copying algorithm. First, reachable objects are marked, then a compacting step relocates the reachable (marked ...
Garbage collection is performed by copying live objects from one semispace (the from-space) to the other (the to-space), which then becomes the new heap. The entire old heap is then discarded in one piece. It is an improvement on the previous stop-and-copy technique. [citation needed] Cheney's algorithm reclaims items as follows: