20 lines
1.1 KiB
Plaintext
20 lines
1.1 KiB
Plaintext
snap
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v. To replace a pointer to a pointer with a direct pointer; to replace an
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old address with the forwarding address found there. If you telephone the
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main number for an institution and ask for a particular person by name, the
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operator may tell you that person's extension before connecting you, in the
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hopes that you will snap your pointer and dial direct next time. The
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underlying metaphor may be that of a rubber band stretched through a number
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of intermediate points; if you remove all the thumbtacks in the middle, it
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snaps into a straight line from first to last. See chase pointers. Often,
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the behavior of a trampoline is to perform an error check once and then snap
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the pointer that invoked it so as henceforth to bypass the trampoline (and
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its one-shot error check). In this context one also speaks of snapping
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links. For example, in a LISP implementation, a function interface
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trampoline might check to make sure that the caller is passing the correct
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number of arguments; if it is, and if the caller and the callee are both
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compiled, then snapping the link allows that particular path to use a direct
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procedure-call instruction with no further overhead.
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