umask Subroutine
  
  
  Purpose
  
  Sets and gets the value of the file creation mask.
  
  Library
  
  Standard C Library (libc.a)
  
  Syntax
  
  #include <sys/stat.h>
  
  mode_t umask (CreationMask)
  mode_t CreationMask;
  
  Description
  
  The umask subroutine sets the file-mode creation mask of the pro-
  cess to the value of the CreationMask parameter and returns the
  previous value of the mask.
  
  Whenever a file is created (by the open, mkdir, or mknod subrou-
  tine),  all  file permission bits set in the file  mode  creation
  mask are cleared in the mode of the created file.  This  clearing
  allows users to restrict the default access to their files.
  
  The mask is inherited by child processes.
  
  Parameters
  
  CreationMask	Specifies the value of the file mode creation mask.
  The CreationMask parameter is constructed by logically ORing file
  permission bits defined in the  sys/mode.h file. Nine bits of the
  CreationMask parameter are significant.
  
  Return Values
  
  If successful, the file permission bits returned by the umask
  subroutine are the previous value of the file-mode creation mask.
  The CreationMask parameter can be set to this value in subsequent
  calls to the umask subroutine, returning the mask to its initial
  state.
  
  Implementation Specifics
  
  This subroutine is part of Base Operating System (BOS) Runtime.
  
  Suggested Reading
  
  
  
  Prerequisite Information
  
   Files, Directories, and File Systems for Programmers in AIX Ver-
  sion 3.2 General Programming Concepts.
  
  Related Information
  
  The  openx, open, or creat subroutine,  chmod subroutine,  mkdir
  subroutine,  mkfifo subroutine,  mknod subroutine,  stat subrou-
  tine.
  
  The  sh command,  ksh command.
  
  The  sys/mode.h file.
  
   Shells Overview in AIX Version 3.2 System User's Guide: Base and
  Devices.