Hi Jetflower, What is the concurrency model of your thread? Is it multi-threaded? INFO: Calling Shell Functions and Interfaces from a Multithreaded Apartment[^] Best Wishes, -David Delaune

Dear Mr enhzflep and Mr DavidCrow, First of all, thank you so much about your clearly explanation. I just still have a consideration, why the small expression (& 0xFFFF) has been still used in the expression ((l) >> 16) & 0xFFFF) here . And this expression origins from window library, hix. Why they still have used this expression if it was not necessary in here ? Once again, thanks for your help, Mr enhzflep and Mr DavidCrow. Best regards, Duong Quoc Thang