FCHOWN(3P) POSIX Programmer's Manual FCHOWN(3P)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.
NAMEfchown — change owner and group of a file
int fchown(int fildes, uid_t owner, gid_t group);
The fchown() function shall be equivalent to chown() except that the
file whose owner and group are changed is specified by the file
Upon successful completion, fchown() shall return 0. Otherwise, it
shall return −1 and set errno to indicate the error.
The fchown() function shall fail if:
EBADF The fildes argument is not an open file descriptor.
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
EROFS The file referred to by fildes resides on a read-only file sys‐
The fchown() function may fail if:
EINVAL The owner or group ID is not a value supported by the implemen‐
tation. The fildes argument refers to a pipe or socket or an
fattach()-ed STREAM and the implementation disallows execution
of fchown() on a pipe.
EIO A physical I/O error has occurred.
EINTR The fchown() function was interrupted by a signal which was
The following sections are informative.
Changing the Current Owner of a File
The following example shows how to change the owner of a file named
/home/cnd/mod1 to ``jones'' and the group to ``cnd''.
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.
struct passwd *pwd;
struct group *grp;
fildes = open("/home/cnd/mod1", O_RDWR);
pwd = getpwnam("jones");
grp = getgrnam("cnd");
fchown(fildes, pwd->pw_uid, grp->gr_gid);
The Base Definitions volume of POSIX.1‐2008, <unistd.h>
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 Electri‐
cal 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 .
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IEEE/The Open Group 2013 FCHOWN(3P)