Free opencv memory

Question

I already have a message about the release of all IplImage and the entire structure of CvMat and CvMemStorage , but still I have memory problems.

Should I also release CvPoint , CvScalar , CvPoint* (an array of 3 CvPoints, do I need to also free every element?)

If I need to release it all, how am I? I did not find any function for this. I am using OpenCV 2.1 in C / C ++.

Here's how I declare them:

 CvScalar b1; CvScalar f; float *data=(float*)resd->imageData; (need to release data) CvPoint *point; CvPoint pt; CvPoint* ptsCorner=(CvPoint*) malloc(3*sizeof(ptsCorner[0])); 

Answer 1

This question is much more related to C than OpenCV. For example, they:

 CvScalar b1; CvScalar f; CvPoint pt; 

are local variables, and therefore they are automatically deactivated when the { } region belonging to them finishes execution.

It:

 CvPoint *point; 

is a pointer and at the same time is a local variable. You should not delete or free() , because you did not allocate any memory for it through new or malloc() . This will cause a problem (possibly a malfunction).

But data on the other hand:

 float *data = (float*)resd->imageData; 

is a pointer and a local variable that contains a block of memory. However, this is unreasonable for delete[] data; or free(data) in this particular case, because you did not allocate this memory directly. Obviously, this memory was allocated as part of resd , which means that you need to check the code and find out how the resd variable was declared / initialized, and then follow the appropriate procedure to release it. Since I know the litle bit about OpenCV, I can say that resd is IplImage* . If you used cvCreateImage() to create this variable, then it is also your task to free it with cvReleaseImage() .

Finally:

 CvPoint* ptsCorner=(CvPoint*) malloc(3*sizeof(ptsCorner[0])); 

This is a typical case of dynamic memory allocation, where you specifically allocate memory. Since ptsCorner is a local variable and a pointer, when the region to which it belongs finishes executing, you will lose a reference to this memory block and it will simply be lost in your RAM, free up memory space and cause a leak. Needless to say, you must execute free() to free memory in this case.

Answer 2

If you initialize the CVPoint structure with new , then yes, you will need to call delete (or delete [] if it is an array) to avoid memory leak.

If not, then when the function goes out of scope, the variables will be automatically destroyed.

If you post your code, it will be easier to see.

Answer 3

I think the best way to solve your problems is to read a good tutorial on pointers.

Here is one http://www.cplusplus.com/doc/tutorial/pointers/

What are you saying, there are OpenCV problems, in fact, this is a lack of understanding of programming languages. So, start with the basics, the ad will continue!