Principles
The basic principles of garbage collection are:
- Find data objects in a program that cannot be accessed in the future
- Reclaim the resources used by those objects
Many computer languages require garbage collection, either as part of the language specification (e.g., Java, C#, and most scripting languages) or effectively for practical implementation (e.g., formal languages like lambda calculus); these are said to be garbage collected languages. Other languages were designed for use with manual memory management, but have garbage collected implementations available (e.g., C, C++). Some languages, like Ada, Modula-3, and C++/CLI allow both garbage collection and manual memory management to co-exist in the same application by using separate heaps for collected and manually managed objects; others, like D, are garbage collected but allow the user to manually delete objects and also entirely disable garbage collection when speed is required. While integrating garbage collection into the language's compiler and runtime system enables a much wider choice of methods, post hoc GC systems exist, including some that do not require recompilation. (Post-hoc GC is sometimes distinguished as litter collection.) The garbage collector will almost always be closely integrated with the memory allocator.
Read more about this topic: Garbage Collection (computer Science)
Famous quotes containing the word principles:
“Language is a process of free creation; its laws and principles are fixed, but the manner in which the principles of generation are used is free and infinitely varied. Even the interpretation and use of words involves a process of free creation.”
—Noam Chomsky (b. 1928)
“I have ever deemed it fundamental for the United States never to take active part in the quarrels of Europe. Their political interests are entirely distinct from ours. Their mutual jealousies, their balance of power, their complicated alliances, their forms and principles of government, are all foreign to us. They are nations of eternal war.”
—Thomas Jefferson (1743–1826)
“The chief lesson of the Depression should never be forgotten. Even our liberty-loving American people will sacrifice their freedom and their democratic principles if their security and their very lives are threatened by another breakdown of our free enterprise system. We can no more afford another general depression than we can afford another total war, if democracy is to survive.”
—Agnes E. Meyer (1887–1970)