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[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]]

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A *file descriptor* is a [[concept]] of [[UNIX]], and represents a
non-[[persistent|persistency]] handle to an object (a file, for example).  With
respect to specific aspects, it is comparable to a [[capability]].
This is detailed in {{$capability#wikipedia_capability-based_security}}.

In a GNU Hurd system, the concept of file descriptors is based on object
handles (through [[Mach ports|microkernel/mach/port]]), and is [[implemented in
glibc|glibc/file_descriptor]].