sub read
{
  @_ == 3 or croak '$shm->read(POS, SIZE)';
  my($self, $pos, $size) = @_;
  my $buf = '';
  if (defined $self->addr) {
    memread($self->addr, $buf, $pos, $size) or return undef;
  }
  else {
    shmread($self->id, $buf, $pos, $size) or return undef;
  }
  $buf;
}

sub write
{
  @_ == 4 or croak '$shm->write(STRING, POS, SIZE)';
  my($self, $str, $pos, $size) = @_;
  if (defined $self->addr) {
    return memwrite($self->addr, $str, $pos, $size);
  }
  else {
    return shmwrite($self->id, $str, $pos, $size);
  }
}

##</code><code>##

read ( POS, SIZE )

Read SIZE bytes from the shared memory segment at POS . Returns the string read, or undef if there was an error. The return value becomes tainted. See shmread.
write ( STRING, POS, SIZE )

Write SIZE bytes to the shared memory segment at POS . Returns true if successful, or false if there is an error. See shmwrite.

##</code><code>##

$shm->write(pack("S", 4711), 2, 2);

##</code><code>##

S  An unsigned short value.