how to free allocated memory in C++ dll function which is called from C# module

Posted on 2015-01-12
Last Modified: 2015-01-19
Dear All

Do we have any methodology to free allocated memory in C++ dll function which is called from C# module.
Its quite urgent.Can u please help.

Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
  • 2
  • +2
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 40544323
Who allocates the memory? Is it the C++ or the C#?
LVL 86

Expert Comment

ID: 40544503
Furthermore, if it is done in the C++ DLL, that will also depend how the allocation was done,, i.e. via 'new', 'new[]', 'malloc()' or some OS-specific API. In other words: That can be quite a simple task if you have the source code and close to impossible if you haven't.

Author Comment

ID: 40546031
Thanks Sir for the reply,

Memory is getting allocated in C++ DLL only.
Actually This DLL cod eis very big and its an ATL COM DLL.Hence so many places BSTR,_bstr_t,and other form of strings are getting used.Moreover its data is very crucially calculated and tested too.Hence we dont want to change the DLL Code.Only when we hit the DLL number of times,then it crashes unexpectedly.

If we can do something from managed code level from C# code,that will be beneficial.

Thanks again.
Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

LVL 86

Expert Comment

ID: 40546595
No, there is hardly anything you could do from managed code. What exactly is the exception that causes the crash?
LVL 23

Assisted Solution

by:Michael Fowler
Michael Fowler earned 250 total points
ID: 40548105
You could look at disposing the COM object after use with Marshal.ReleaseComObject

This method is used to explicitly control the lifetime of a COM object used from managed code. You should use this method to free the underlying COM object that holds references to resources in a timely manner or when objects must be freed in a specific order.

Author Comment

ID: 40548230
@jkr, the popup just triggered at server that w3wp.exe stopped you want to debug.when we say ok then again service starts working atleast for some time.Earlier also it happened so many times.

@Michaels,actually I am already using it but I am not sure whether it is fulfilling the requirement or not.
LVL 23

Expert Comment

by:Michael Fowler
ID: 40548239
Another suggestion is that it well known that when using the Office Interop that you need to release all objects created under the initial com object. When using the office interop it is highly recommended to never use an expression with 2 dots but rather decalre objects for these objects eg

Something similar could be happening here
LVL 22

Accepted Solution

ambience earned 250 total points
ID: 40549297
Often there is no easy way to catch and fix such problems. There are a few things worth a try:

Setup Drwatson or enable coredump writing in Windows. This should give you something to analyze under WinDbg, which will at least tell about the nature of crash, exception codes etc.

As for memory issues, you might have to resort to profiling the application using 3rd party tools, open/free or paid.

Featured Post

Creating Instructional Tutorials  

For Any Use & On Any Platform

Contextual Guidance at the moment of need helps your employees/users adopt software o& achieve even the most complex tasks instantly. Boost knowledge retention, software adoption & employee engagement with easy solution.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article will show, step by step, how to integrate R code into a R Sweave document
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.

617 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question