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 permission 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 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 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 .