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help needed :( Memory leak

Started by Striken Mar 10, 2004 at 3:11 PM 3 replies 350+ views

Original Post

Mar 10, 2004 at 3:11 PM

I''ve got a problem with pointers and memory etc. Ok here''s the situation. I create a mesh temporarily. Mesh details get stored i.e.: tempMesh.face[1].vert = new CVertexID[3]; the function ends. the temporary mesh is drawn. >> the old mesh must be DELETED << a new temporary mesh is created the function ends etc. What I need to do, is (i presume) store the location of the array of (in this example''s case) CVertexID, and delete[] the contents of that on the next pass around. So I''m thinking something along the lines of CVertexID *p_oldVert; p_oldVert = &tempMesh.face[1].vert; then on next time the function is called: delete[] p_oldVert; OR SOMETHING ALONG THOSE LINES! ** confused ** Since the function MUST end before it is drawn, I think the correct references go out of context and so I can''t access them correctly. Please if you have any insight, I have been stuck with this problem for about a week or two now. This is a core function so the memory leak over time is unacceptable!

smart_idiot

183

smart_idiot

Mar 10, 2004 at 3:18 PM

// vert of the 2nd element of tempMesh.face points to 3 CVertexID objects. So far so good.
tempMesh.face[1].vert = new CVertexID[3];

// Pointer to a vertex. Also okay.
CVertexID *p_oldVert;

// Assigning a pointer to the pointer to the CVertexID array. They are different types, this should generate a warning or something.
p_oldVert = &tempMesh.face[1].vert;

// No good can come from this; it''s pointing to a) the wrong type, and b) it points to the inside of another object.
delete[] p_oldVert;

Striken

Author

Striken

Mar 10, 2004 at 5:23 PM

Ok thanks, but it still doesn''t help me get anywhere near an answer!

I think I conceptually understand the problem, it''s just implementing it I''m not entirely sure about. Here''s the deal:

1) Create an array of pointers
2) Store the Address of the array of Pointers
3) Draw the Mesh structure
4) Delete the array of pointers using the address
5) Re-Create array of pointers.

So I create the array of pointers:
tempMesh.face[0].vert = new CVertexID[3];

Store the address:
?? How do I define the variable that stores the address?
CVertexID ?? I''m not sure about this.

Draw the Mesh...

Delete the array
delete[] p_arrayOldVertexID

reassign

Please help

ForeverStarlight

Mar 10, 2004 at 6:57 PM

Striken,

What smart_idiot was trying to say, is that:

tempMesh.face[1].vert

is a pointer to the CVertexID array, that means:

&tempMesh.face[1].vert;

is a pointer to a pointer. . . So,

p_oldVert = tempMesh.face[1].vert;

would be the correct way of pointing p_oldVert to the array. There is also the fact that tempMesh.face[1].vert is still has the address of the array even after you delete it through p_oldVert. So make sure that is not a problem. . . tempMesh is a local variable of the function then you are safe, as the object is destroyed before the array.

Or you could redesign to avoid this seperation by passing tempMesh as a reference parameter , and delete the array directly after the function adn drawing is done.

Hope I understood your problem correctly and this helps.

Striken

Author

Striken

Mar 10, 2004 at 9:07 PM

It''s hurting my brain this problem! To make matters worse is that the whole thing is being referenced as a pointer for the draw function as an external dll so I can''t just take it out and redesign it without completely overhauling the system.

your help has brought me closer to understanding exactly what''s going on, thanks a million guys

I''ll let you know how it goes.

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