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33 .Nd delete a descriptor
43 system call deletes a descriptor from the per-process object
45 If this is the last reference to the underlying object, the
46 object will be deactivated.
47 For example, on the last close of a file
50 pointer associated with the file is lost;
51 on the last close of a
53 associated naming information and queued data are discarded;
54 on the last close of a file holding an advisory lock
55 the lock is released (see further
57 However, the semantics of System V and
61 advisory record locks associated with a file for a given process
64 file descriptor for that file is closed by that process.
67 all associated file descriptors are freed, but since there is
68 a limit on active descriptors per processes, the
71 is useful when a large quantity of file descriptors are being handled.
73 When a process forks (see
75 all descriptors for the new child process reference the same
76 objects as they did in the parent before the fork.
77 If a new process is then to be run using
79 the process would normally inherit these descriptors.
81 of the descriptors can be rearranged with
87 is attempted, but if some of these descriptors will still
88 be needed if the execve fails, it is necessary to arrange for them
89 to be closed if the execve succeeds.
90 For this reason, the call
91 .Dq Li fcntl(d, F_SETFD, FD_CLOEXEC)
93 which arranges that a descriptor will be closed after a successful
95 .Dq Li fcntl(d, F_SETFD, 0)
97 which is to not close the descriptor.
103 system call will fail if:
109 is not an active descriptor.
111 An interrupt was received.
113 The underlying object did not fit, cached data was lost.
115 The underlying object was a stream socket that was shut down by the peer
116 before all pending data was delivered.
119 In case of any error except
121 the supplied file descriptor is deallocated and therefore is no longer valid.
135 system call is expected to conform to