freebsd-dev/lib/libc/sys/unlink.2
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.\" @(#)unlink.2 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd December 10, 2006
.Dt UNLINK 2
.Os
.Sh NAME
.Nm unlink
.Nd remove directory entry
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn unlink "const char *path"
.Sh DESCRIPTION
The
.Fn unlink
system call
removes the link named by
.Fa 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 process 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.
The
.Fa path
argument
may not be a directory.
.Sh RETURN VALUES
.Rv -std unlink
.Sh ERRORS
The
.Fn unlink
succeeds unless:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 characters.
.It Bq Er ENOENT
The named file does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er EACCES
Write permission is denied on the directory containing the link
to be removed.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EPERM
The named file is a directory.
.It Bq Er EPERM
The named file has its immutable, undeletable or append-only flag set, see the
.Xr chflags 2
manual page for more information.
.It Bq Er EPERM
The parent directory of the named file has its immutable or append-only flag
set.
.It Bq Er EPERM
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.
.It Bq Er EIO
An I/O error occurred while deleting the directory entry
or deallocating the inode.
.It Bq Er EROFS
The named file resides on a read-only file system.
.It Bq Er EFAULT
The
.Fa path
argument
points outside the process's allocated address space.
.El
.Sh SEE ALSO
.Xr chflags 2 ,
.Xr close 2 ,
.Xr link 2 ,
.Xr rmdir 2 ,
.Xr symlink 7
.Sh HISTORY
The
.Fn unlink
function appeared in
.At v6 .
.Pp
The
.Fn unlink
system call traditionally allows the super-user to unlink directories which
can damage the file system integrity.
This implementation no longer permits
it.