aStemLib Type

This is an opaque type that represents the aStem Library.  The actual underlying implementation of this depends on the platform and may change at any time.  To obtain a reference to the library for use in calling all library routines, use the aStem_GetLibRef routine and when you are done with it, be sure to call aStem_ReleaseLibRef routine to free up any resources used by the library.

aHeartbeatCallback Type

This is a procedure pointer that allows you to do custom processing in response to heartbeat packets.  This type has the following declaration:

typedef aErr (*aHeartbeatCallback)(const aBool bOn, void* ref);

The aBool type passes the current state of the heartbeat to the user's routine.  The void pointer may refer to a user's own data structure.

aPacketRef Type

This is an opaque type that represents a packet.  The actual underlying implementation of this depends on the platform and may change at any time.  This type is used in all places where data is sent to or from the BrainStem modules.  Using this packet abstraction will enable you to port your code across platforms by just recompiling.  It also allows you to benefit from any changes, compression, or error checking and correction that may be employed on the actual packet protocol.  This packet reference can be created using the aPacket_Create routine.  In general, packets are disposed of by sending them to the module using the aStem_SendPacket routine.

aPacketFilter Type

This is a procedure pointer that allows you to filter the packets received from the aStem_GetPacket routine.

aSTEMMAXPACKETBYTES

This #define determines the maximum number of data (payload) bytes that may be sent in a given packet .  This is defined in the "aStem.h" file.