ultrix man page for umask

umask(2)							System Calls Manual							  umask(2)

Name
       umask - set file creation mask

Syntax
       #include <sys/types.h>
       #include <sys/stat.h>

       oumask = umask(numask)
       mode_t oumask, numask;

Description
       The  system  call sets the process's file mode creation mask to and returns the previous value of the mask.  The low-order nine bits of are
       used whenever a file is created, clearing corresponding bits in the file mode.  (For further information, see  This  clearing  allows  each
       user to restrict the default access to his or her files.

       The value is initially 022 (write access for owner only).  The mask is inherited by child processes.

       The previous value of the file mode mask is returned by the call.

Environment
       POSIX
       When your program is compiled in POSIX mode, the numask argument is of type mode_t and the function returns a value of type mode_t.

See Also
       chmod(2), mknod(2), open(2)

																	  umask(2)