'\" et

.TH FCHOWN "3P" 2013 "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

fchown

\(em change owner and group of a file

.SH SYNOPSIS

.LP

.nf

#include <unistd.h>

.P

int fchown(int \fIfildes\fP, uid_t \fIowner\fP, gid_t \fIgroup\fP);

.fi

.SH DESCRIPTION

The

\fIfchown\fR()

function shall be equivalent to

\fIchown\fR()

except that the file whose owner and group are changed is

specified by the file descriptor

.IR fildes .

.SH "RETURN VALUE"

Upon successful completion,

\fIfchown\fR()

shall return 0. Otherwise, it shall return \(mi1 and set

.IR errno

to indicate the error.

.SH ERRORS

The

\fIfchown\fR()

function shall fail if:

.TP

.BR EBADF

The

.IR fildes

argument is not an open file descriptor.

.TP

.BR EPERM

The effective user ID does not match the owner of the file or the

process does not have appropriate privileges and _POSIX_CHOWN_RESTRICTED

indicates that such privilege is required.

.TP

.BR EROFS

The file referred to by

.IR fildes

resides on a read-only file system.

.P

The

\fIfchown\fR()

function may fail if:

.TP

.BR EINVAL

The owner or group ID is not a value supported by the implementation.

The

.IR fildes

argument refers to a pipe or socket

or an

\fIfattach\fR()-ed

STREAM

and the implementation disallows execution of

\fIfchown\fR()

on a pipe.

.TP

.BR EIO

A physical I/O error has occurred.

.TP

.BR EINTR

The

\fIfchown\fR()

function was interrupted by a signal which was caught.

.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 owner of a file named

.BR /home/cnd/mod1

to ``jones'' and the group to ``cnd''.

.P

The numeric value for the user ID is obtained by extracting the user ID

from the user database entry associated with ``jones''. Similarly, the

numeric value for the group ID is obtained by extracting the group ID

from the group database entry associated with ``cnd''. This example

assumes the calling program has appropriate privileges.

.sp

.RS 4

.nf

\fB

#include <sys/types.h>

#include <unistd.h>

#include <fcntl.h>

#include <pwd.h>

#include <grp.h>

.P

struct passwd *pwd;

struct group  *grp;

int            fildes;

\&...

fildes = open("/home/cnd/mod1", O_RDWR);

pwd = getpwnam("jones");

grp = getgrnam("cnd");

fchown(fildes, pwd->pw_uid, grp->gr_gid);

.fi \fR

.P

.RE

.SH "APPLICATION USAGE"

None.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIchown\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<unistd.h>\fP"

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 7, Copyright (C) 2013 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group.

(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

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 .