PowerBuilder enhances runtime support for multithreaded applications.

Applications that use shared objects can run in multithreaded environments. Previously, the
PowerBuilder .NET runtime library did not provide a way to synchronize data, so the data
was susceptible to corruption. Additionally, locking mechanisms for accessing static
fields in previous versions of PowerBuilder made assemblies using NVO instances
susceptible to problems associated with reentrance.

In PowerBuilder 12.5, the runtime library has been changed to solve the NVO assembly problem with static fields. You can also use .NET Thread and .NET thread synchronization functions for multithreaded applications.

See Using Multithreading for support in the PowerBuilder .NET IDE, or
Using .NET Synchronization for PowerBuilder Classic.