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UMASK(3P)                  POSIX Programmer's Manual                 UMASK(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.
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 process' file mode creation mask  to
       cmask  and return the previous value of the mask. Only the file permis-
       sion bits of cmask (see <sys/stat.h>) are  used;  the  meaning  of  the
       other bits is implementation-defined.
       The  process'  file  mode creation mask is used during open(), creat(),
       mkdir(), and mkfifo() to turn off permission bits in the mode  argument
       supplied.  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 unspec-
       ified 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
       IEEE Std 1003.1-2001.
FUTURE DIRECTIONS
       None.
SEE ALSO
       creat(), mkdir(), mkfifo(), open(),  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <sys/stat.h>, <sys/types.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  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 .

IEEE/The Open Group                  2003                            UMASK(3P)