PHP Manual . ... PHP 4 >= 4.0.4) shmop_read -- Read data from shared memory block . string shmop_read ( int shmid, int start, int count) . shmop_read() will read a string from shared memory block. shmop_read() takes 3 parameters: shmid, which is the shared memory block identifier created by shmop_open() , offset from which to start reading and count on the number of bytes to read. ... This example will read 50 bytes from shared memory block and place the data inside $shm_data . ...