Usually when the phrase “thread safe” is used it means that the same instance of the library can be accessed by different threads at the same time.
This means that Foxit Quick PDF Library is not thread safe because a single instance of Foxit Quick PDF Library can only be accessed by the thread that created the instance.
However, Foxit Quick PDF Library can be used in a multi-threaded environment so long as a separate instance of the library is created by each thread.
For users of the ActiveX edition of the library, please note that this version has been compiled with the threading mode set to “single threaded apartment”.