Function Code

The Function Code contains a unique value, defining the message type. This is combined with a set of modifier flags that provide for minor expansions to the "pure" set of commands.

The least significant 5 bits of the Function Code contains the command code. This gives a set of 32 possible commands. Command code 0 is, defensively, not used, giving a total of 31 commands, of which only five are defined:

Code Name

Value

Meaning

#FNF_PING

1

Ping packet. No message.

#FNF_ACK

2

Acknowledgement of an #FNF_RPC. No message.

#FNF_SESSION

3

Session management table in message.

#FNF_RPC

4

RPC in message.

#FNF_ RPCMULTI

5

Multiple RPCs in message.

The most significant 3 bits contain modifier flags. These flags are command specific and are presently only defined for image\Number_Hatch.gifFNF_RPC:

Flag Name

Value

Meaning

#FNF_FLAG_RESERVED

32

Reserved for future use.

#FNF_FLAG_FIRST

64

First fragment of a fragmented RPC.

#FNF_FLAG_NEXT

128

Subsequent fragment of a fragmented RPC