shmreadID,VAR,POS,SIZE
This function reads from the shared memory segment ID starting at
position POS for size SIZE (by attaching to it, copying out, and
detaching from it). VAR must be a variable that will hold the data
read. The function returns true if successful, or false if there is
an error. On error, it puts the error code into $!. This
function is available only on machines supporting System V IPC.