UMASK
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
umask
--- set and get the file mode creation mask
SYNOPSIS
#include <sys/stat.h>
mode_t umask(mode_t cmask);
DESCRIPTION
The
umask()
function shall set the file mode creation mask of the process to
cmask
and return the previous value of the mask. Only the file permission
bits of
cmask
(see
<sys/stat.h>)
are used; the meaning of the other bits is implementation-defined.
The file mode creation mask of the process is used to turn off
permission bits in the
mode
argument supplied during calls to the following functions:
- *
-
open(),
openat(),
creat(),
mkdir(),
mkdirat(),
mkfifo(),
and
mkfifoat()
- *
-
mknod(),
mknodat()
- *
-
mq_open()
- *
-
sem_open()
Bit positions that are set in
cmask
are cleared in the mode of the created file.
RETURN VALUE
The file permission bits in the value returned by
umask()
shall be the previous value of the file mode creation mask. The state
of any other bits in that value is unspecified, except that a
subsequent call to
umask()
with the returned value as
cmask
shall leave the state of the mask the same as its state before the
first call, including any unspecified use of those bits.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
Unsigned argument and return types for
umask()
were proposed. The return type and the argument were both changed to
mode_t.
Historical implementations have made use of additional bits in
cmask
for their implementation-defined purposes. The addition of the text
that the meaning of other bits of the field is implementation-defined
permits these implementations to conform to this volume of POSIX.1-2008.
FUTURE DIRECTIONS
None.
SEE ALSO
creat(),
exec,
mkdir(),
mkfifo(),
mknod(),
mq_open(),
open(),
sem_open()
The Base Definitions volume of POSIX.1-2008,
<sys_stat.h>,
<sys_types.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
-
- APPLICATION USAGE
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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