free - finding the size of the pointer to free.

[wmjenkinson]

I have the following but it does not seem to work. I want to decrement the size of memory pointed to be pBlock.

void free (void *pBlock)
{
THeapBlockHeader *pBlockHeader = (THeapBlockHeader *) ((uintptr) pBlock - sizeof (THeapBlockHeader));

//mem_usage -= pBlockHeader->nSize;

CMemorySystem::HeapFree (pBlock);

}

[rsta2]

pBlock can be 0, you have to filter this out.

[wmjenkinson]

Not sure if I follow you, what I am trying to achieve is when free a pointer that say points to 10 bytes, that when I free it, it will take 10 bytes from the global value, "mem_usage".

`void *malloc (size_t nSize)
{
void * ptr = CMemorySystem::HeapAllocate (nSize, HEAP_DEFAULT_MALLOC);

if(ptr != nullptr){
	mem_usage += nSize;
	memset (ptr, 0, nSize);
}
return ptr;

}`

`void free (void *pBlock)
{
if(ptr != nullptr){

	THeapBlockHeader *pBlockHeader = (THeapBlockHeader *) ((uintptr) pBlock - sizeof (THeapBlockHeader));

	mem_usage -= pBlockHeader->nSize;

	CMemorySystem::HeapFree (pBlock);
}

}`

[rsta2]

Yes. Another problem can be, that these functions can be called at IRQ_LEVEL and maybe from multiple cores. You should protect the variable mem_usage with a spin lock, or use atomic access functions in <circle/atomic.h>. If you still have problems, I need more info, what happens.

[wmjenkinson]

Yeah, I'm aware of the concurrency issue.