FCHMOD
Section: POSIX Programmer's Manual (3P)
Updated: 2013
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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.
NAME
fchmod
--- change mode of a file
SYNOPSIS
#include <sys/stat.h>
int fchmod(int fildes, mode_t mode);
DESCRIPTION
The
fchmod()
function shall be equivalent to
chmod()
except that the file whose permissions are changed is specified
by the file descriptor
fildes.
If
fildes
references a shared memory object, the
fchmod()
function need only affect the S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP,
S_IROTH, and S_IWOTH file permission bits.
If
fildes
references a typed memory object, the behavior of
fchmod()
is unspecified.
If
fildes
refers to a socket, the behavior of
fchmod()
is unspecified.
If
fildes
refers to a STREAM (which is
fattach()-ed
into the file system name space) the call returns successfully, doing
nothing.
RETURN VALUE
Upon successful completion,
fchmod()
shall return 0. Otherwise, it shall return -1 and set
errno
to indicate the error.
ERRORS
The
fchmod()
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 and the
process does not have appropriate privileges.
- EROFS
-
The file referred to by
fildes
resides on a read-only file system.
The
fchmod()
function may fail if:
- EINTR
-
The
fchmod()
function was interrupted by a signal.
- EINVAL
-
The value of the
mode
argument is invalid.
- EINVAL
-
The
fildes
argument refers to a pipe and the implementation disallows execution of
fchmod()
on a pipe.
The following sections are informative.
EXAMPLES
Changing the Current Permissions for a File
The following example shows how to change the permissions for a
file named
/home/cnd/mod1
so that the owner and group have read/write/execute permissions, but
the world only has read/write permissions.
-
#include <sys/stat.h>
#include <fcntl.h>
mode_t mode;
int fildes;
...
fildes = open("/home/cnd/mod1", O_RDWR);
fchmod(fildes, S_IRWXU | S_IRWXG | S_IROTH | S_IWOTH);
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
chmod(),
chown(),
creat(),
fcntl(),
fstatat(),
fstatvfs(),
mknod(),
open(),
read(),
write()
The Base Definitions volume of POSIX.1-2008,
<sys_stat.h>
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 .
Index
- PROLOG
-
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- EXAMPLES
-
- Changing the Current Permissions for a File
-
- APPLICATION USAGE
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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