Ccomptr idispatch queryinterface call

Mfc has the easiesttoimplement, zippiest version of idispatch aroundall you. No, you should always you queryinterface just because youve com an iunknown interface it doesnt mean you can directly cast it to idispatch. The reflexive property refers to the ability for the queryinterface call on a. We use cookies for various purposes including analytics. Create and use ccomptr and ccomqiptr instances github. Contribute to seleniumhqselenium development by creating an account on github. Mfc supports idispatch and com aggregation, you dont have to do a lot to get those features up and. An interface based solely on idispatch is called a dispinterface. The vtable of a dispinterface is identical to that of idispatch itself.

Stack overflow for teams is a private, secure spot for you and your coworkers to find and share information. Ccomptr is a basic smart pointer that wraps com interface pointers. By continuing to use pastebin, you agree to our use of cookies as described in the cookies policy. Run ilogic rule from external application manufacturing.

Ccomqiptr is for cases when you want to call queryinterface in a. I have a dual idispatch interface of documentwindow class, related to powerpoint. Youll soon see a version of this function that calls queryinterface. Call a method by dispid or name, passing zero parameters. But the reason i said i am led to believe it is quite ok to use ccomptr with coclasses not just interfaces is due to the responses to a. Ccomptr provides a specialization for idispatch that enables it to store pointers to com automation components and invoke the methods on the interface by using late binding. The next line will always have a successful hr value because it comes from the previous success already checked and not from the queryinterface call. The windows mfc active template library atl information and. Idispatch this interface provides namebased dynamic method dispatch for. You use different idl attributes depending on whether you are implementing a pure idispatch interface or a dual interface.

The ccomptr calls release automatically when object is destroyed when program ends. With ccomqiptr, the return value is the pointer itself, and if the call fails, the internal. How to cast dual interfaces of microsoft powerpoint. Ccomptr provides a specialization for idispatch that enables it to store. Atl compiler error c2594 ambiguous conversions fromto. Ccomptr is still a mystery to me, though i have tried the function call with and without an initialized com pointer. The problem here is that if the idispatch is null then the hr is never set by the line that fetches the irequest pointer. This destroys ccomptr instance stored in the map, which in turn calls release, matching the earlier queryinterface call. Com may have given you a proxy to the underlying object, which means that the pointer has nothing to do with idispatch likewise, an implementation may wrap an object that implements idispatch and when you call queryinterface it delegates to this object.