'\" et
.TH LCHOWN "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
lchown
\(em change the owner and group of a symbolic link
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>
.P
int lchown(const char *\fIpath\fP, uid_t \fIowner\fP, gid_t \fIgroup\fP);
.fi
.SH DESCRIPTION
The
\fIlchown\fR()
function shall be equivalent to
\fIchown\fR(),
except in the case where the named file is a symbolic link. In this
case,
\fIlchown\fR()
shall change the ownership of the symbolic link file itself, while
\fIchown\fR()
changes the ownership of the file or directory to which the symbolic
link refers.
.SH "RETURN VALUE"
Upon successful completion,
\fIlchown\fR()
shall return 0. Otherwise, it shall return \-1 and set
.IR errno
to indicate an error.
.SH ERRORS
The
\fIlchown\fR()
function shall fail if:
.TP
.BR EACCES
Search permission is denied on a component of the path prefix of
.IR path .
.TP
.BR EINVAL
The owner or group ID is not a value supported by the implementation.
.TP
.BR ELOOP
A loop exists in symbolic links encountered during resolution of the
.IR path
argument.
.TP
.BR ENAMETOOLONG
.br
The length of a component of a pathname is longer than
{NAME_MAX}.
.TP
.BR ENOENT
A component of
.IR path
does not name an existing file or
.IR path
is an empty string.
.TP
.BR ENOTDIR
A component of the path prefix names an existing file that is neither
a directory nor a symbolic link to a directory, or the
.IR path
argument contains at least one non-\c
<slash>
character and ends with one or more trailing
<slash>
characters and the last pathname component names an existing file
that is neither a directory nor a symbolic link to a directory.
.TP
.BR EPERM
The effective user ID does not match the owner of the file and the
process does not have appropriate privileges.
.TP
.BR EROFS
The file resides on a read-only file system.
.P
The
\fIlchown\fR()
function may fail if:
.TP
.BR EIO
An I/O error occurred while reading or writing to the file system.
.TP
.BR EINTR
A signal was caught during execution of the function.
.TP
.BR ELOOP
More than
{SYMLOOP_MAX}
symbolic links were encountered during resolution of the
.IR path
argument.
.TP
.BR ENAMETOOLONG
.br
The length of a pathname exceeds
{PATH_MAX},
or pathname resolution of a symbolic link produced an intermediate
result with a length that exceeds
{PATH_MAX}.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
.SS "Changing the Current Owner of a File"
.P
The following example shows how to change the ownership of the symbolic
link named
.BR /modules/pass1
to the user ID associated with ``jones'' and the group ID associated
with ``cnd''.
.P
The numeric value for the user ID is obtained by using the
\fIgetpwnam\fR()
function. The numeric value for the group ID is obtained by using the
\fIgetgrnam\fR()
function.
.sp
.RS 4
.nf

#include <sys/types.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
.P
struct passwd *pwd;
struct group  *grp;
char          *path = "/modules/pass1";
\&...
pwd = getpwnam("jones");
grp = getgrnam("cnd");
lchown(path, pwd->pw_uid, grp->gr_gid);
.fi
.P
.RE
.SH "APPLICATION USAGE"
On implementations which support symbolic links as directory entries
rather than files,
\fIlchown\fR()
may fail.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIchown\fR\^(\|)",
.IR "\fIsymlink\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<unistd.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .