— remove directory
fd, const char
function removes the link named by path from its
directory and decrements the link count of the file which was referenced by
the link. If that decrement reduces the link count of the file to zero, and
no process has the file open, then all resources associated with the file
are reclaimed. If one or more processes have the file open when the last
link is removed, the link is removed, but the removal of the file is delayed
until all references to it have been closed.
function is equivalent to either the
rmdir(2) function depending on the value of
flag (see below), except that where
path specifies a relative path, the directory entry to
be removed is determined relative to the directory associated with file
descriptor fd instead of the current working
is passed the special value
AT_FDCWD (defined in
<fcntl.h>) in the
fd parameter, the current working directory is used
and the behavior is identical to a call to
or rmdir(2), depending on whether or not the
AT_REMOVEDIR bit is set in
The flag argument is the bitwise OR of zero or more of the following values:
- Remove the directory entry specified by path as a directory, not a normal file.
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.
unlinkat() functions will fail if:
- A component of the path prefix is not a directory.
- A component of a pathname exceeded
NAME_MAXcharacters, or an entire pathname (including the terminating NUL) exceeded
- The named file does not exist.
- Search permission is denied for a component of the path prefix.
- Write permission is denied on the directory containing the link to be removed.
- Too many symbolic links were encountered in translating the pathname.
- The named file is a directory and the effective user ID of the process is
not the superuser, or the file system containing the file does not permit
the use of
unlink() on a directory.
- The directory containing the file is marked sticky, and neither the containing directory nor the file to be removed are owned by the effective user ID.
- The named file or the directory containing it has its immutable or append-only flag set (see chflags(2)).
- The entry to be unlinked is the mount point for a mounted file system.
- An I/O error occurred while deleting the directory entry or deallocating the inode.
- The named file resides on a read-only file system.
- path points outside the process's allocated address space.
unlinkat() will fail if:
AT_REMOVEDIRflag bit is set and path does not name a directory.
AT_REMOVEDIRflag bit is set and the named directory contains files other than ‘
.’ and ‘
..’ in it.
- The value of the flag argument was neither zero nor
- The value of the flag argument was
AT_REMOVEDIRand the last element of path consists of ‘
- The path argument specifies a relative path and the
fd argument is neither
AT_FDCWDnor a valid file descriptor.
- The path argument specifies a relative path and the fd argument is a valid file descriptor but it does not reference a directory.
- The path argument specifies a relative path but search permission is denied for the directory which the fd file descriptor references.
rm(1), chflags(2), close(2), link(2), rmdir(2), symlink(7)
unlinkat() functions conform to
IEEE Std 1003.1-2008 (“POSIX.1”).
unlink() system call first appeared in
Version 1 AT&T UNIX. The
unlinkat() function appeared in