Perl5 リファレンス

       shmread ID,VAR,POS,SIZE

       shmwrite ID,STRING,POS,SIZE
               Reads or writes the System V shared memory segment
               ID starting at position POS for size SIZE by
               attaching to it, copying in/out, and detaching
               from it.  When reading, VAR must be a variable
               that will hold the data read.  When writing, if
               STRING is too long, only SIZE bytes are used; if
               STRING is too short, nulls are written to fill out
               SIZE bytes.  Return true if successful, or false
               if there is an error.  shmread() taints the
               variable. See also `IPC::SysV' documentation and
               the `IPC::Shareable' module from CPAN.