| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
CLOSE(2) Linux Programmer's Manual CLOSE(2)
close - close a file descriptor
#include <unistd.h>
int close(int fd);
close() closes a file descriptor, so that it no longer refers to any file and
may be reused. Any record locks (see fcntl(2)) held on the file it was
associated with, and owned by the process, are removed (regardless of the file
descriptor that was used to obtain the lock).
If fd is the last file descriptor referring to the underlying open file
description (see open(2)), the resources associated with the open file
description are freed; if the descriptor was the last reference to a file
which has been removed using unlink(2) the file is deleted.
close() returns zero on success. On error, -1 is returned, and errno is set
appropriately.
EBADF fd isn't a valid open file descriptor.
EINTR The close() call was interrupted by a signal; see signal(7).
EIO An I/O error occurred.
SVr4, 4.3BSD, POSIX.1-2001.
Not checking the return value of close() is a common but nevertheless serious
programming error. It is quite possible that errors on a previous write(2)
operation are first reported at the final close(). Not checking the return
value when closing the file may lead to silent loss of data. This can
especially be observed with NFS and with disk quota.
A successful close does not guarantee that the data has been successfully
saved to disk, as the kernel defers writes. It is not common for a file
system to flush the buffers when the stream is closed. If you need to be sure
that the data is physically stored use fsync(2). (It will depend on the disk
hardware at this point.)
It is probably unwise to close file descriptors while they may be in use by
system calls in other threads in the same process. Since a file descriptor
may be reused, there are some obscure race conditions that may cause
unintended side effects.
fcntl(2), fsync(2), open(2), shutdown(2), unlink(2), fclose(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 2007-12-28 CLOSE(2)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface