umask(2)                                                 umask(2)



NAME
     umask - set and get file creation mask

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

     mode_t umask(cmask)
     mode_t cmask;

DESCRIPTION
     umask sets the file-mode-creation mask of the calling
     process to cmask and returns the previous value of the mask.
     Only the low-order 9 bits of cmask and the file-mode-
     creation mask are used.

     The file-mode-creation mask is used whenever a file is
     created by creat(2), mknod(2) or open(2).  The actual mode
     (see chmod(2)) of the newly created file is the difference
     between the given mode and cmask.  In other words, cmask
     shows the bits to be turned off when a new file is created.

     For the POSIX environment, the following constants for cmask
     are defined in <sys/stat.h>:

     S_IRUSR
          read permission, owner

     S_IWUSR
          write permission, owner

     S_IXUSR
          execute/search permission, owner

     S_IRGRP
          read permission, group

     S_IWGRP
          write permission, group

     S_IXGRP
          execute/search permission, group

     S_IRUSR
          read permission, others

     S_IWUSR
          write permission, others

     S_IXUSR
          execute/search permission, others




January 1992                                                    1

umask(2)                                                 umask(2)



     The previous value of cmask is returned by the call.  The
     value is initially 022, which is an octal ``mask'' number
     representing the complement of the desired mode.  The value
     022 here means that no permissions are withheld from the
     owner, but write permission is forbidden to the group and to
     others. Its complement, the mode of the file, would be 0755.
     The file-mode-creation mask is inherited by child processes.

STATUS MESSAGES AND VALUES
     The previous value of the file-mode-creation mask is
     returned.

SEE ALSO
     chmod1(2), creat(2), mknod(2), open(2)

     csh(1), ksh(1), chmod(1), mkdir(1), sh(1) in A/UX Command
     Reference






































2                                                    January 1992