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unlinkat() - Unix, Linux System Call


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NAME

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

SYNOPSIS

#include <fcntl.h> 

int unlinkat(int dirfd, const char *pathname, int flags);

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 flags is defined:

TagDescription
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():

TagDescription
EBADF dirfd is not a valid file descriptor.
EINVAL An invalid flag value was specified in flags.
ENOTDIR pathname is a relative path and dirfd is a file descriptor referring to a file other than a directory.

NOTES

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

CONFORMING TO

This system call is non-standard but is proposed for inclusion in a future revision of POSIX.1. A similar system call exists on Solaris.

VERSIONS

unlinkat() was added to Linux in kernel 2.6.16.

SEE ALSO



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