LAP Implementation Issues (Windows CE 5.0)
When creating a LAP, keep in mind the following implementation issues:
Often LAPs require a fallback mechanisim. For example, in the case of a fingerprint LAP, there is often an ability to enter a strong password if the fingerprint recognition engine fails. Such mechanisms are LAP-dependent, and must be implemented in the LAP itself.
When LASS makes the following calls, a global LASS lock is held. As a result, LAPs should not block any longer than necessary when implementing these calls:
- VerifyUserStart
- VerifyUserStop
- VerifyUser with VU_NO_UI flag set
If a LAP spawns a new thread, the newly created thread should not make any calls back into LASS. If it does, it is possible to cause a deadlock.
When you implement a LAP, it is important to consider what the behavior should be when VerifyUser is called before the user has been enrolled. The two recommended behaviors are:
- VerifyUser returns TRUE until the user enrolls.
- Enrollment is forced on the first call to VerifyUser.
The default password LAP implements the first option.
See Also
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