v7 man page for umask

UMASK(2)							System Calls Manual							  UMASK(2)

NAME
       umask - set file creation mode mask

SYNOPSIS
       umask(complmode)

DESCRIPTION
       Umask  sets a mask used whenever a file is created by creat(2) or mknod(2): the actual mode (see chmod(2)) of the newly-created file is the
       logical and of the given mode and the complement of the argument.  Only the low-order 9 bits of the mask (the protection bits) participate.
       In other words, the mask shows the bits to be turned off when files are created.

       The  previous  value of the mask is returned by the call.  The value is initially 0 (no restrictions).  The mask is inherited by child pro-
       cesses.

SEE ALSO
       creat(2), mknod(2), chmod(2)

ASSEMBLER
       (umask = 60.)
       sys umask; complmode

																	  UMASK(2)