Calls the System V IPC function msgrcv to receive a message from
message queue ID into variable VAR with a maximum message size of
SIZE. Note that when a message is received, the message type as a
native long integer will be the first thing in VAR, followed by the
actual message. This packing may be opened with unpack("l! a*")
.
Taints the variable. Returns true if successful, or false if there is
an error. See also SysV IPC in perlipc, IPC::SysV
, and
IPC::SysV::Msg
documentation.