unlink.2   [plain text]


.\"	$NetBSD: unlink.2,v 1.7 1995/02/27 12:39:13 cgd Exp $
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.\"     @(#)unlink.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt UNLINK 2
.Os BSD 4
.Sh NAME
.Nm unlink
.Nd remove directory entry
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fo unlink
.Fa "const char *path"
.Fc
.Sh DESCRIPTION
The
.Fn unlink
function
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.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn unlink
system call will fail if:
.Bl -tag -width Er
.\" ===========
.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 EBUSY
The entry to be unlinked is the mount point for a
mounted file system.
.\" ===========
.It Bq Er EBUSY
The file named by the
.Fa path
argument cannot be unlinked
because it is being used by the system or by another process.
.\" ===========
.It Bq Er EFAULT
.Fa Path
points outside the process's allocated address space.
.\" ===========
.It Bq Er EIO
An I/O error occurs while deleting the directory entry
or deallocating the inode.
.\" ===========
.It Bq Er ELOOP
Too many symbolic links are encountered in translating the pathname.
This is taken to be indicative of a looping symbolic link.
.\" ===========
.It Bq Er ENAMETOOLONG
A component of a pathname exceeds
.Dv {NAME_MAX}
characters, or an entire path name exceeds
.Dv {PATH_MAX}
characters (possibly as a result of expanding a symlink).
.\" ===========
.It Bq Er ENOENT
The named file does not exist.
.\" ===========
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.\" ===========
.It Bq Er EPERM
The named file is a directory and the effective user ID
of the process is not the super-user.
.\" ===========
.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 EROFS
The named file resides on a read-only file system.
.El
.Sh SEE ALSO
.Xr close 2 ,
.Xr link 2 ,
.Xr rmdir 2 ,
.Xr symlink 7
.Sh HISTORY
An
.Fn unlink
function call appeared in 
.At v6 .