Re: Invalid chunk ptr after exiting app

[Richard Coutts]

I've been reading through the architives and seeing that this is likely
because I'm overwriting a chunk header, or something to that effect.  My
apps pretty big, so I'm having a tough time tracking down where this 
might
be happening.  When I make changes to the code, it sometimes goes away,
but
it appears as though this is only because the bug is effecting less
critical
parts of memory.
One approach for tracking memory overwrites is to add 'sentinel'
markers to the beginning and end of each block and check these
when you release the block (or at any other time you want to look
for memory overwrite).
The mechanism for memory problem debugging is to write small
functions called something like DebugMemHandleNew,
DebugMemHandleFree, etc.  These functions take the same parameters
as the system functions but do some extra stuff on each memory alloc
and release before calling the system functions.  'Extra stuff' varies
depending on the problem you're having, but it might be adding four
bytes of marker to the beginning and end of each allocated block, or
writing a log of each allocation and release (good for tracking 
lock/release
problems).  You then create a C header that #defines MemHandleNew
to  DebugMemHandleNew, etc for each function and add this header to
every C file in your project.
Thanks Chris, I definately need to do this.
Does anyone have this code posted somewhere or be willing to share it with 
me?  To say that I'm under a time constraint, would be an understatement.

Thanks,
Rich 

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