Linux manual pages Section 2: System Calls  

Name

unlinkat — remove a directory entry relative to a directory file descriptor

Synopsis

#include <fcntl.h> /* Definition of AT_* constants */
#include <unistd.h>
int unlinkat( int dirfd,
  const char *pathname,
  int flags);
 
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
unlinkat():
Since glibc 2.10:
_XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_ATFILE_SOURCE

DESCRIPTION

The unlinkat() system call operates in exactly the same way as either unlink(2) or rmdir(2) (depending on whether or not flags includes the AT_REMOVEDIR flag) except for the differences described in this manual page.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by unlink(2) and rmdir(2) for a relative pathname).

If the pathname given in pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory of the calling process (like unlink(2) and rmdir(2)).

If the pathname given in pathname is absolute, then dirfd is ignored.

flags is a bit mask that can either be specified as 0, or by ORing together flag values that control the operation of unlinkat(). Currently only one such flag is defined:

AT_REMOVEDIR

By default, unlinkat() performs the equivalent of unlink(2) on pathname. If the AT_REMOVEDIR flag is specified, then performs the equivalent of rmdir(2) on pathname.

RETURN VALUE

On success, unlinkat() returns 0. On error, −1 is returned and errno is set to indicate the error.

ERRORS

The same errors that occur for unlink(2) and rmdir(2) can also occur for unlinkat(). The following additional errors can occur for unlinkat():

EBADF

dirfd is not a valid file descriptor.

EINVAL

An invalid flag value was specified in flags.

ENOTDIR

pathname is relative and dirfd is a file descriptor referring to a file other than a directory.

VERSIONS

unlinkat() was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4.

CONFORMING TO

POSIX.1-2008. A similar system call exists on Solaris.

NOTES

See openat(2) for an explanation of the need for unlinkat().

SEE ALSO

openat(2), rmdir(2), unlink(2), path_resolution(7)

COLOPHON

This page is part of release 3.52 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/.


  This manpage is Copyright (C) 2006, Michael Kerrisk

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