delete a descriptor
call deletes a descriptor d from the per-process
object reference table. If this is the last reference to the underlying
object, the object will be deactivated. For example, on the last close of a
file, the current
pointer associated with the file is lost; on the last close of a
associated naming information and queued data are discarded; and on the last
close of a file holding an advisory lock, the lock is released (see
However, the semantics of System V and IEEE Std 1003.1-1988
(“POSIX.1”) dictate that all
advisory record locks associated with a file for a given process are removed
file descriptor for that file is closed by that process.
When a process forks (see
descriptors for the new child process reference the same objects as they did
in the parent before the fork. If a new process image is to then be run
using execve(2), the process would normally inherit these descriptors. Most
of the descriptors can be rearranged with
before the execve(2) is attempted, but since some of these descriptors may still
be needed should the execve(2) fail, it is necessary to arrange for them to be
closed when the execve(2) succeeds. For this reason, the call
F_SETFD, FD_CLOEXEC) is
provided, which arranges that a descriptor will be closed after a successful
F_SETFD, 0) restores the
default, which is to not close the descriptor.
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
close() will fail if:
- d is not an active descriptor.
- An interrupt was received.
- An I/O error occurred while writing to the file system.
accept(2), closefrom(2), dup2(2), execve(2), fcntl(2), flock(2), open(2), pipe(2), socket(2), socketpair(2)
close() conforms to IEEE
Std 1003.1-2008 (“POSIX.1”).
close() system call first appeared in
Version 1 AT&T UNIX.