30 lines
1.5 KiB
Text
30 lines
1.5 KiB
Text
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A memory leak occurs when a Perl data structure is destroyed but some of
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the contents of that structure are not freed. Leaked memory is a useless
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overhead. Leaks can significantly impact system performance. They can also
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cause an application to abend due to lack of memory.
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In Perl, circular references are a common cause of memory leaks. Circular
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references are allowed in Perl, but data structures containing circular
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references will leak memory unless the programmer takes specific measures
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to prevent leaks. Preventive measures include weakening the references
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and arranging to break the reference cycle just before the structure is
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destroyed.
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When using circular references, it is easy to misdesign or misimplement a
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scheme for preventing memory leaks. Mistakes of this kind have been hard to
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detect in a test suite.
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Test::Weaken allows easy detection of unfreed Perl data. Test::Weaken allows
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you to examine the unfreed data, even data that would usually have been made
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inaccessible.
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Test::Weaken frees the test structure, then looks to see if any of the
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contents of the structure were not actually deallocated. By default,
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Test::Weaken determines the contents of a data structure by examining
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arrays and hashes, by following references, and by following tied variables
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to their underlying object. Test::Weaken does this recursively to unlimited
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depth.
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Test::Weaken can deal with circular references without going into infinite
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loops. Test::Weaken will not visit the same Perl data object twice.
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