DDS15 — Definition of BuiltinTopicKey_t

The PSM mapping of BuiltinTopicKey_t is defined to be as:

struct BuiltinTopicKey_t { 
    BUILTIN_TOPIC_KEY_TYPE_NATIVE value[3]; 
}; 

But the DDS Interoperability Wire Protocol (RTPS) specifies that GUID consists of 12 bytes GuidPrefix and 4 bytes EntityId.

In order to map GUID and BuiltinTopicKey, we should define BuiltinTopicKey as either

typedef octet BuiltinTopicKey[16];

or else if we really wanted to preserve the definition as an array of longs

struct BuiltinTopicKey_t { 
    BUILTIN_TOPIC_KEY_TYPE_NATIVE value[4]; 
}; 

But the latter could cause problems due to different endianess unless we also specified how to place the octets that arrive at the protocol level into the array of long.