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memory leak problem...
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Join Date: Mar 2006
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Hi!
I built this class, however when I executed my program the memory run out quickly, because I wasn't making any "deletes", so I added the delete in the destructor, but It crashes there... what's wrong?
I built this class, however when I executed my program the memory run out quickly, because I wasn't making any "deletes", so I added the delete in the destructor, but It crashes there... what's wrong?
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C Syntax (Toggle Plain Text)
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Join Date: Dec 2005
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What does SetMaxColRow() actually do?
If you just construct and destruct this object in a test program, does it still crash?
Have you looked at what other things are doing elsewhere? Just because it crashes here doesn't mean the problem is here, when dealing with dynamic memory.
If you just construct and destruct this object in a test program, does it still crash?
Have you looked at what other things are doing elsewhere? Just because it crashes here doesn't mean the problem is here, when dealing with dynamic memory.
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Originally Posted by gampalu
Hi!
I built this class, however when I executed my program the memory run out quickly, because I wasn't making any "deletes", so I added the delete in the destructor, but It crashes there... what's wrong?
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Originally Posted by Salem
What does SetMaxColRow() actually do?
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Am I doing the correct delete , concerning the "new's" I made?
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Originally Posted by Salem
If you just construct and destruct this object in a test program, does it still crash?
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Originally Posted by Salem
Have you looked at what other things are doing elsewhere? Just because it crashes here doesn't mean the problem is here, when dealing with dynamic memory.
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> m_nCols = NULL;
> m_nRows = NULL;
NULL typically signifies a pointer, so this is sending the wrong message to the reader
Just do
> memset(m_pMatriz, 0.0, sizeof(long double) * m_nRows * m_nCols);
http://c-faq.com/malloc/calloc.html
Filling the memory with 0 (even though you said 0.0, this is not what you get) does not guarantee a useful floating point value.
A simple loop is enough
> I have looked arround the code and found no problems, at least for me, an inexperienced programmer
Without lots of tools, pros find this hard to do as well.
Lots of testing at all stages, and walkthroughs with the debugger help you to understand what's really happening.
> m_nRows = NULL;
NULL typically signifies a pointer, so this is sending the wrong message to the reader
Just do
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> memset(m_pMatriz, 0.0, sizeof(long double) * m_nRows * m_nCols);
http://c-faq.com/malloc/calloc.html
Filling the memory with 0 (even though you said 0.0, this is not what you get) does not guarantee a useful floating point value.
A simple loop is enough
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> I have looked arround the code and found no problems, at least for me, an inexperienced programmer
Without lots of tools, pros find this hard to do as well.
Lots of testing at all stages, and walkthroughs with the debugger help you to understand what's really happening.
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Originally Posted by Ancient Dragon
Nothing wrong with what you posted -- its impossible to tell what the proglem is because you didn't post enough code. Check for (1) writing outside allocated array bounds, (2) using uninitialized pointers.
(2) I haven't uninitialized pointers.
I'll put all the code of the class:
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Thanks in advance for helping
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Originally Posted by Salem
> m_nCols = NULL;
> m_nRows = NULL;
NULL typically signifies a pointer, so this is sending the wrong message to the reader
Just do
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Originally Posted by Salem
> memset(m_pMatriz, 0.0, sizeof(long double) * m_nRows * m_nCols);
http://c-faq.com/malloc/calloc.html
Filling the memory with 0 (even though you said 0.0, this is not what you get) does not guarantee a useful floating point value.
A simple loop is enough
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Originally Posted by Salem
> I have looked arround the code and found no problems, at least for me, an inexperienced programmer
Without lots of tools, pros find this hard to do as well.
Lots of testing at all stages, and walkthroughs with the debugger help you to understand what's really happening.
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output:
C Syntax (Toggle Plain Text)
Last edited by Dave Sinkula; Jun 1st, 2006 at 2:45 pm. Reason: Added quote tags to help with my confusion.
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> *(m_pMatriz + k * m_nCols + k) = 1.0;
In many places in your class member functions, you have this complex row/col calculation.
In other places, you call SetElement() and GetElement()
With the exception of the Set and Get functions, nothing should be aware of how the data is actually accessed. That is, all your other member functions should use the Set and Get methods.
Which OS and compiler are you using?
For Linux, consider using 'valgrind' or 'electric fence'
> int main
It would be really useful if you could produce a simple main() which did show up a problem.
In many places in your class member functions, you have this complex row/col calculation.
In other places, you call SetElement() and GetElement()
With the exception of the Set and Get functions, nothing should be aware of how the data is actually accessed. That is, all your other member functions should use the Set and Get methods.
Which OS and compiler are you using?
For Linux, consider using 'valgrind' or 'electric fence'
C Syntax (Toggle Plain Text)
> int main
It would be really useful if you could produce a simple main() which did show up a problem.
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Originally Posted by Salem
> *(m_pMatriz + k * m_nCols + k) = 1.0;
In many places in your class member functions, you have this complex row/col calculation.
In other places, you call SetElement() and GetElement()
With the exception of the Set and Get functions, nothing should be aware of how the data is actually accessed. That is, all your other member functions should use the Set and Get methods.
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Which OS and compiler are you using?
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So the problem should be that, having nothing to do with delete!
How do you suggest me to find?
Thank you for all your attention and patiente
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> the variable m_pMatriz is double* and the GetElement and SetElement are methods for CMatrix types
But those functions take and return doubles, so there should be no problem.
They're used fine in some contexts already anyway.
I've attached your code with Set/Get used in many more places, and it compiles fine here.
The //!! comments are what my g++ compiler spotted with
$ g++ -c -W -Wall -ansi -pedantic -O2 foo.cpp
Oh, you might want to rename all your loop variables from i,j to be say r,c to denote row and column. It's not always clear whether you're accessing the correct element of the array (when you're doing it directly), and r/c would make it more readable IMO.
At least by always using the set/get functions, every access is properly range checked (as it should be).
But those functions take and return doubles, so there should be no problem.
They're used fine in some contexts already anyway.
I've attached your code with Set/Get used in many more places, and it compiles fine here.
The //!! comments are what my g++ compiler spotted with
$ g++ -c -W -Wall -ansi -pedantic -O2 foo.cpp
Oh, you might want to rename all your loop variables from i,j to be say r,c to denote row and column. It's not always clear whether you're accessing the correct element of the array (when you're doing it directly), and r/c would make it more readable IMO.
At least by always using the set/get functions, every access is properly range checked (as it should be).
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