How does a tokend's probe() function work?

Question

SecTokend.h declares a function

CSSM_RETURN (*probe)(SecTokendProbeFlags flags, uint32 *score, char tokenUid[TOKEND_MAX_UID]);

which is called by securityd at some point. But I can't find when and how it is called.
a) On which conditions does tokend call this function?
b) How is probe() supposed to know for which device it has to look?

TIA

Answer 1

• Tokend is deprecated from Lion onwards.
• Tokend gets a reader name as parameter
• probe is called to test if this tokend can handle the given card (it is supposed to return a score, and the tokend with the best score will win the inserted card)