Multithreading and contexts

From version 1.2.0 pcsc-lite is much more multithreading friendly.

You have to follow some rules:

• For security reasons, a context can only be released (using SCardReleaseContext()) by the thread that created it.

• To access different readers (i.e. cards) in different threads, each thread must use a different context (not necessarily created by this thread itself).

Each thread should create his own context with SCardEstablishContext() and should release it with SCardReleaseContext() when the context is not necessary any more.

If different threads share a same context, the calls to different functions of the pcsc-lite API are stored in a queue and the executions serialised for this context because there is a mutex shared for all the (critical) operations of this context.

Note: The SCF (Smart Card Framework) used by Solaris has not been updated. So if you compile pcsc-lite using ./configure -enable-scf you will still have a global lock mechanism.