Operating in a Multithreaded Environment

The fax service calls FaxDevStartJob at the beginning of a new fax job and once for each fax operation, because each operation executes in a separate thread. Fax service providers must function in a multithreaded environment.

The fax service provider must allocate memory for the job-specific instance data for each fax operation thread to ensure that the fax service provider DLL is thread-safe. The fax service provider should also deallocate memory for the instance data when the fax operation finishes. For more information, see Multiple Threads.