redhat man page for close

CLOSE(2)						     Linux Programmer's Manual							  CLOSE(2)

NAME
       close - close a file descriptor

SYNOPSIS
       #include <unistd.h>

       int close(int fd);

DESCRIPTION
       close  closes  a  file  descriptor, so that it no longer refers to any file and may be reused. Any locks 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 copy of a particular file descriptor the resources associated with it are freed; if the descriptor was the last reference
       to a file which has been removed using unlink(2) the file is deleted.

RETURN VALUE
       close returns zero on success, or -1 if an error occurred.

ERRORS
       EBADF  fd isn't a valid open file descriptor.

       EINTR  The close() call was interrupted by a signal.

       EIO    An I/O error occurred.

CONFORMING TO
       SVr4, SVID, POSIX, X/OPEN, BSD 4.3.  SVr4 documents an additional ENOLINK error condition.

NOTES
       Not  checking the return value of close is a common but nevertheless serious programming error.	It is quite possible that errors on a pre-
       vious 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 disk quotas.

       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 filesystem 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.)

SEE ALSO
       open(2), fcntl(2), shutdown(2), unlink(2), fclose(3), fsync(2)

								    2001-12-13								  CLOSE(2)