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Invalidating site reference com

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There are a few alternatives to cache invalidation that still deliver updated content to the client.One alternative is to expire the cached content quickly by reducing the time-to-live (TTL) to a very low value.

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For instance, when a sequence container such as requires an underlying reallocation, outstanding iterators, pointers, and references will be invalidated [Kalev 99].Cache invalidation is a process in a computer system whereby entries in a cache are replaced or removed.It can be done explicitly, as part of a cache coherence protocol.After the cache is invalidated, if the client requests the cache, they are delivered a new version.There are three specific methods to invalidate a cache, but not all caching proxies support these methods. When the client requests the data again, it is fetched from the application and stored in the caching proxy.The C Standard allows references and pointers to be invalidated independently for the same operation, which may result in an invalidated reference but not an invalidated pointer.

However, relying on this distinction is insecure because the object pointed to by the pointer may be different than expected even if the pointer is valid.

For instance, it is possible to retrieve a pointer to an element from a container, erase that element (invalidating references when destroying the underlying object), then insert a new element at the same location within the container causing the extant pointer to now point to a valid, but distinct object.

Thus, any operation that invalidates a pointer or a reference should be treated as though it invalidates both pointers and references.

An erase operation that erases the first element of a deque but not the last element invalidates only the erased elements.

An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. Invalidates all references, pointers, and iterators referring to the elements of the container and may invalidate the past-the-end iterator.

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