For a list of possible values, see the wflags parameter in idispatch invoke in the windows sdk. Jan 03, 2010 so, today my mind has been 100 % focused on something that on the surface looks really boring. The idispatch mechanism has a performance overhead to package parameters compared to a pure vtable com call. You can, of course, just manually break the cycles at strategic points to prevent leaks, but a better solution is to have more sophisticated garbage collection. Im trying to run my methods on my automationobject through the method invoke in the idispatch interface. In order to try to track these leaks, im using redgates ants memory profiler. This module provides commands for implementing com clients in tcl. In essence, idispatch represents a standard vtable with a highly extensible invocation architecture. Dec 01, 2010 due to many developers dont know how access the wmi from pascal code, i decided to write this entry to show a simple set of samples using delphi win32, delphi. After running for a couple of hours, the applications memory footprint grows to a size of over 200mb. Im trying to run my methods on my automationobject through the method invoke in the idispatchinterface.
Extending iunknown, it is one of the standard interfaces that can be exposed by com objects. For implementing com servers, see the com server module. The requested member does not exist, or the call to invoke tried to set the value of a readonly property. If you are chasing memory leaks then youd be looking for missing. This page was last modified on 28 march 2012, at 19. Misunderstanding idl parameter direction leading to bstr. Personally, i find cyclic references to be useful, and resent the restriction.
Though 64bit applications have much more memory space, memory leaks can still cause significant problems. Atl generated code for idispatch invoke method is incorrect. Fixes a memory leak that occurs when you frequently open and close an mfc application that uses the cmfcribbonbar class to implement ribbon bars in visual studio 2010 sp1 if the categories and buttons use. Winehq wine announcement the wine development release. Understanding and correcting interface reference leaks in. Idispatchexinvokeex provides all of the same features as idispatchinvoke and adds a few extensions. After implementing the workaround, i could go upto 60,000 iterations. Lets go through that code a line at a time and see what could be better. Exe com server invokation leaking handles rick strahls web log.
The most serious of these problems is the performance of idispatchbased components. The client queries the object using idispatch methods, and then executes the method via invoke. In fact, invoke is the only way to execute a userdefined method through the idispatch interface. So even for that, it is not easy to determine what memory to break for.
How to create a dual dispatch interface powerbasic peer. This means instead of the source calling directly onto a method in a sink, the call is made via the idispatch invoke mechanism. Task manager to see how much memory it takes and it seems its a memory leak in there. Like a dispinterface, a dual interface supports early binding and late binding. Begininvoke calls are the source of at least some of the leaks. Does reference count for idispatch increase when i pass it to my function as a pointer. On 32bit operating systems, where memory space is limited to around 3 gigabytes per process, leaks can increase memory required by any given application to the point where memory runs out and the application crashes. Invoke actually calls a method or a property exposed by the com object through idispatch.
Invoke performs a call to a latebinded property or method. Idispatch is the interface that exposes the ole automation protocol. The from my thread i am displaying the dialog as shown bellow. May 16, 2016 hi kim, i would suggest you try the following steps to see the outcome. Delphi 5 calls idispatchinvoke with wrong parameters. That thread needs to show a dialog inputdlg to get some user input. Having to call both idispatchgetidsofnames to get the dispatch ids, then idispatchinvoke to make the call, is a lot of overhead. If your pvar holds an interface pointer iunknown or idispatch, you.
I have tens of idispatch objects, so what if i forget to release any of them. Idispatch interface can anyone help me with the idispatch interface. In which cases refence count for idispatch is increased. Jan 07, 20 with only a partial idispatch vtable all kinds of badness could happen e. You can, of course, just manually break the cycles at strategic points to prevent leaks, but a better solution is. Memory leaks i believe i found another potential memory leaks in wxautomationobject invoke. An outbound interface can be a pure dispatch interface. Where can i find information about how invoke works and how returnvalues are managed and what the parameters in tdispparams are fore and so on.
The side that is eventually responsible for freeing the memory is still the caller. This suggested the memory we were leaking was not allocated by delphi code. In computer science, a memory leak is a type of resource leak that occurs when a computer program incorrectly manages memory allocations in such a way that. Add a test for the memory pointed to by a byref parameter being preserved through a remote idispatchinvoke call. Here would be about the simplest example i can come up with of reading a line of data from an excel. Aug 17, 2004 ots of good responses to my challenge of yesterday. Writing idispatch code by hand is cruel and unusual punishment, best left to. As you can see, idispatch is a single physical interface that allows less sophisticated clients to get at any number of logical interfaces. Based on the results ive captured, it appears that my dispatcher. Thats normally the return value, decorated with out,retval. Atl provides some macros to assist with listening to idispatch events. Flags describing the context of the call to idispatch invoke. If you dont have a git account, you cant do anything here.
Net in general are the most common cause of memory leaks. One of the parameters in rgvarg could not be coerced to the specified type. Fixes a memory leak that occurs when you frequently open and close an mfc application that uses the cmfcribbonbar class to implement ribbon bars in visual studio 2010 sp1 if. Actually, if well strictly follow the definition above, classic memory leaks are not possible in. When the intern method is invoked, the method checks the pool to see if an. Cannot pass an idispatch parameter to a method called with idispatch invoke. Note that odbc drivers are a standard or system install on all versions of windows going as far back as i can remember, which would be windows 95 or thereabouts. Is there any easy way to release all idispatch or i have to release them only manually. Exit all office applications then perform an online repair referring to repair an office application. Without the workaround i was able to run 57,000 iterations. The interval is cancelled before our dotnetobjectreference is disposed so our javascript doesnt try to invoke a method on a. A lot of you probably heard the name idispatch before. The other common problem involves out parameters which are not inout or outretval parameters.
The most serious of these problems is the performance of idispatch based components. Solution to spot the defect part two fabulous adventures in. This means instead of the source calling directly onto a method in a sink, the call is made via the idispatchinvoke mechanism. The mfc library steps in on both sides of the invoke call, using a datadriven scheme to call component functions based on dispatch map parameters that you define with. This implementation of idispatch does not support named parameters. If the handle has been set, we invoke our new javascript blazouniversity. Thats one reason idispatchinfo is declared as a private nested interface in dispatchutility. A dual interface derives from idispatch and uses only automationcompatible types. Delphi 5 calls idispatch invoke with wrong parameters. I used the wizard to create a single object with the atl wizards, added some method to its idispatchgenerated interface and let the attribute provider generate the idispatch code.
In the situation where the client is unmanaged, the memory leak did not show up. Obtain type information of idispatchbased com objects from. Todo a short description of this collection of constants. The first 6 refer to managed memory leaks and the last 2 to unmanaged memory leaks. Memory leak is detected when we are creating stdthread object. You can add a comment by following this link or if you reported this bug, you can edit this bug over here. If you do, then the subsequent memory leaks are entirely your own fault, apparently. I think i could have found another problem with the atl generated code for idispatchinvoke. In, out, inout, make up your mind already fabulous. Those are allocated at lines 1192 and freed only at lines 187189. From what i understand, idispatch and invoke are used to support late bound clients. Like other scripting languages such as vbscript and javascript, twapis com support is focused on automation objects through their idispatch and idispatchex interfaces. If the function exits on line 150 or 172, individual bstrs in argnames are not freed. However, the callee may choose to free it and then reallocate new memory.
Idispatchimpl provides a default implementation for the idispatch part of any dual interface on an object. Writing idispatch code by hand is cruel and unusual punishment, best left to a machine that uses the type library. As you can see, its a simple class that implements the idispatch interface. How do i fix memory leaks with windows wpfs dispatcher. Causing a memory leak is very easy with events if you dont know what. Memory leak in an mfc application that is developed in. Once you subscribe to an event, that object holds a reference to your class. One variation has been that memory in the stack around the class has been clobbered.
See the idispatch documentation for a full description of the excepinfo structure. Memory leaks i believe i found another potential memory leaks in wxautomationobjectinvoke. However, no leaks were detected using these tools, although we could see the memory usage increasing in task manager on our test machines. Accesing the wmi from object pascal code delphi, oxygene. It has the additional facility of being able to execute methods as remote. Cannot pass an idispatch parameter to a method called with idispatchinvoke. But still there appears to be a considerable memory leak problem.