[RESOLVED] Memory problem passing BYTE array to thread

[hmc]

I am trying to pass a BYTE array to a thread. This is done using the PostThreadMessage() function and passing the BYTE array as the WPARAM parameter and the number of bytes in the array as LPARAM parameter.
See below.

BYTE* pData = new BYTE(MB_REQ_BUFSIZE);
	if(pData != NULL)
	{
		FillMemory(pData, MB_REQ_BUFSIZE, 0);
		memcpy(pData, m_aRequest, MB_REQ_BUFSIZE);
		
		m_pSerialWriter->PostThreadMessage(UWM_DATA_SEND, (WPARAM)pData, (LPARAM)MB_REQ_BUFSIZE);
	}

In the OnDataSend() handler of the thread i want to retrieve the BYTE* from WPARAM and use it. This all works well, however when i try do delete the array in this handler a assertion message pops up saying "Damage after NORMAL block (#526) at 0x00ADBBC0".

Following this assertion takes me to DBGHEAP.c into the following code:

if (!CheckBytes(pbData(pHead) + pHead->nDataSize, _bNoMansLandFill, nNoMansLandSize))
                _RPT3(_CRT_ERROR, "DAMAGE: after %hs block (#%d) at 0x%08X.\n",
                    szBlockUseName[_BLOCK_TYPE(pHead->nBlockUse)],
                    pHead->lRequest,
                    (BYTE *) pbData(pHead));

The way i try to delete the BYTE array is:

OnSendData(WPARAM wParam, LPARAM lParam)
{
  BYTE* pData = (BYTE*)wParam;
  int iNrBytes = (int)lParam;
  ...
  delete[] pData;
}

[ZuK]

 BYTE* pData = new BYTE(MB_REQ_BUFSIZE);

this allocates only one byte.

Guess you want

 BYTE* pData = new BYTE[MB_REQ_BUFSIZE];

Kurt

[hmc]

Wow, you are sharp! Thanx man!

[TheCPUWizard]

Also memory allocation and deallocation [for a specific] block should ALWAYS be done from the same thread.

[TheCPUWizard]

Also memory should always be allocated/released from the same thread. There is no guarentee that multiple threads will be using the same heap.

[hmc]

CPUWizard, do you have a suggestion how i can allocate/deallocate the BYTE buffer in this case because PostThreadMessage() does not wait for completion.

Now i allocate memory in main thread, pass it to the workerthread and this will release memory as soon as it has done processing.

[MrBeans]

You could WFSO (WaitForSingleObject) on the thread, check return code using GetExitCodeThread for success if so delete the memory in the main thread.