CLOSE

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
NOTES
SEE ALSO

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.

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. File system implementations which use techniques as ‘‘write-behind’’ to increase performance may lead to write(2) succeeding, although the data has not been written yet. The error status may be reported at a later write operation, but it is guaranteed to be reported on closing the file. 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.

SEE ALSO

open(2), fcntl(2), shutdown(2), unlink(2), fclose(3)