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28 .\" @(#)close.2 8.2 (Berkeley) 4/19/94
36 .Nd delete a descriptor
46 system call deletes a descriptor from the per-process object
48 If this is the last reference to the underlying object, the
49 object will be deactivated.
50 For example, on the last close of a file
53 pointer associated with the file is lost;
54 on the last close of a
56 associated naming information and queued data are discarded;
57 on the last close of a file holding an advisory lock
58 the lock is released (see further
60 However, the semantics of System V and
64 advisory record locks associated with a file for a given process
67 file descriptor for that file is closed by that process.
70 all associated file descriptors are freed, but since there is
71 a limit on active descriptors per processes, the
74 is useful when a large quantity of file descriptors are being handled.
76 When a process forks (see
78 all descriptors for the new child process reference the same
79 objects as they did in the parent before the fork.
80 If a new process is then to be run using
82 the process would normally inherit these descriptors.
84 of the descriptors can be rearranged with
90 is attempted, but if some of these descriptors will still
91 be needed if the execve fails, it is necessary to arrange for them
92 to be closed if the execve succeeds.
93 For this reason, the call
94 .Dq Li fcntl(d, F_SETFD, FD_CLOEXEC)
96 which arranges that a descriptor will be closed after a successful
98 .Dq Li fcntl(d, F_SETFD, 0)
100 which is to not close the descriptor.
106 system call will fail if:
112 is not an active descriptor.
114 An interrupt was received.
116 The underlying object did not fit, cached data was lost.
118 The underlying object was a stream socket that was shut down by the peer
119 before all pending data was delivered.
133 system call is expected to conform to