free() question

[DoraC]

Hi,

I am requesting arrays of free-store memory as follows:

ppvMemoryBlock =
( void** )calloc( iSize
                 ,sizeof( void* ) );

am referencing it (after allocating the
constituent void* values) as follows:

myFunction( *(ppvMemoryBlock + iArrayCounter) );

Both of which work fine. But,

free( ppvInMemoryBlock + iArrayCounter );

fails. Shouldn't I be able to free individual units of memory returned as a group by calloc, as I'm trying to do here?

Thanks!
dora c

 

[Salem]

That depends, is the change from
ppvMemoryBlock
to
ppvInMemoryBlock

just a typo when you posted, or is it really that in your code?

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[DoraC]

That's really in my code... they're actually different variables but point to the same address.

Sorry about that - I was trying to slice my code down to something postable and understandable and forgot that...

dora c

 

[cdlvj]

myFunction( *(ppvMemoryBlock + iArrayCounter) );

I think you are referencing the middle of a word.
Why are you doing this and not
ppvMemoryBlock[iArrayCounter];

Depending on the size to store the address, doing it like you are has to increment iArrayCounter by two or four.

 

[Salem]

cdlvj, the two are equivalent
Though personally, I find the array notation a lot cleaner to look at.

DoraC
How do you allocate each row of the array, that is
*(ppvMemoryBlock + iArrayCounter) = calloc ....

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