shkey_t shmsg_t::src_key
source peer of message.
shkey_t shmsg_t::dest_key
destination peer of message.
uint32_t shmsg_t::msg_qid
message queue id
uint32_t shmsg_t::msg_size
total size of message content
uint32_t shmsg_t::msg_of
offset of message data
uint32_t shmsg_t::__reserved_1__
type of message