asked on

properly delete pointer - hopefully a quickie

The loop below is toggled by a "preview" button. It show the images just fine, but it runs my memory up fast because if I put the line "cvReleaseImage(&pimage_copy) anywhere to release the memory, I get a passing null pointer even though I think I am destroying pointers as I create them. How do I reconcile? Should I use smart pointers?

while (CameraStatusInst.Start_Button_Status(false, false))
	{
     IplImage* pimage_copy = contour_image;
 
                                    if (pimage_copy != NULL)
                                        {
                                         int key=0;
                                         cvNamedWindow("Mouse Vision", 1);
                                         cvShowImage("Mouse Vision", pimage_copy);
                                         key = cvWaitKey(20);
                                        //cvReleaseImage(&pimage_copy)    <-------------works when commented out
                                        }
                                        else
                                        {
                                        cvReleaseImage(&pimage_copy);
                                        }
 
 
    }

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SOLUTION

jkr

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Jaime Olivares

try with:

while (CameraStatusInst.Start_Button_Status(false, false))
{
     IplImage* pimage_copy = cvCloneImage(contour_image);
 
    if (pimage_copy != NULL)
    {
          int key=0;
          cvNamedWindow("Mouse Vision", 1);
          cvShowImage("Mouse Vision", pimage_copy);
          key = cvWaitKey(20);
          cvReleaseImage(&pimage_copy)
    }
}

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itsmeandnobodyelse

>>>> cvReleaseImage(&pimage_copy)
you pass the 'address' of pimage_copy to cvReleaseImage. So cvReleaseImage takes a IplImage** ?? That is strange beside cvReleaseImage would expect an array of IplImage pointers rather than a single pointer.

>>>> while (CameraStatusInst.Start_Button_Status(false, false))
>>>> {
>>>> IplImage* pimage_copy = contour_image;

I can't see how that in that while loop you ever would get a pimage_copy == NULL. Even then, why do you call cvReleaseImage(&pimage_copy); with the address of a NULL pointer. What do you expect from that?

I would guess the above loop would fail in the second iteration cause I can't see how contour_image could get a different value (or NULL) in the meantime.

Regards, Alex

SOLUTION

Deepu Abraham

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Wanderinglazyeye

ASKER

Its filling the correct values - the preview window opens up, and the expected images are seen. I removed the loop (pimage_copy == NULL), it works fine. yeah my brain farted.

IplImage* pimage_copy = cvCloneImage(contour_image);
Tried this and releasing it, get run time errors.

Problem is a memory leak when I open the preview window and stops when I close it. It jumps by 10k/second (about) until program crashes. I preview the images by using the sharing image solution shown in another EE topic that was solved earlier. My preview code is a thread launched from a GUI event.

Would it be helpful to anyone to post the entire thread?

SOLUTION

jkr

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ASKER CERTIFIED SOLUTION

itsmeandnobodyelse

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Wanderinglazyeye

ASKER

I dropped the loop. In fact, I dropped the threads. I took your idea about the evaluating whether threads were necessary, and simply made two program versions. One with threads, one without. What I found was that the version without thread BLAZED. Still, it provided a learning experience.

Thanks ItsMe

WLE