Debugging memory leaks

[gmgarrison]

Here is an example of the errors I'm trying to correct:

{3208} normal block at 0x00F452D0, 17 bytes long.
Data: <GGARRISON > 47 47 41 52 52 49 ...

This information is given after memory leaks on detected and the debugger dumps the objects. Can anyone give any general tips on resolving these leaks? Particularly, VC++ complains that various memory allocations are too large by a certain number of bytes. What is the likely culprit?? Does having the data and memory address of the allocation do anything for me after the program has exited? Finally, I can't figure out what the {3208} signifies... If anyone has any tips or suggestions, I'd appreciate it!!

Thanks,
Greg

 

[KeithBrautigam]

Judging by the stuff in angle brackets, <GGARRISON >, I'd say that you're leaking a character buffer containing your name. So I would first look at the code where such a buffer is intended to be allocated and freed.

{3208} is some sort of request number. It appears to come from line the following line:

_RPT1(_CRT_WARN, &quot;{%ld} &quot;, pHead->lRequest);

On my system, at least, that's line 1984 of &quot;c:\program files\microsoft visual studio\vc98\crt\src\dbgheap.c&quot;.

As a general tip, I put the following lines at the top of all my .CPP files:

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

That has the effect of giving me the file and line from which the memory was allocated. For instance, if I write this sloppy code on line 66 of &quot;MemoryTestDoc.cpp&quot;:

new int; // obvious memory leak

Then I might get the following trace:
Detected memory leaks!
Dumping objects ->
D:\MemoryTest\MemoryTestDoc.cpp(66) : {91} normal block at 0x00770030, 4 bytes long.
Data: < > CD CD CD CD
Object dump complete.

The down side of this is that I think it might only work with MFC projects. I'm really not sure.

Anyway, for more info, please try:

http://msdn.microsoft.com/library/default.asp?URL=/library/techart/memleaks.htm

Also, there's a guy by the name of John Robbins who knows lots of stuff about debugging. You can find one of his articles on memory leaks at

http://msdn.microsoft.com/library/default.asp?URL=/library/periodic/period97/dembugs.htm

His web site may be found at

http://www.wintellect.com/robbins/