Using new in one thread and delete in another - getting assert

Hello

I am doing this in a worker thread:

char* szPartial = new char[strlen(szBuffer )+1];
if (szPartial)
{
lstrcpy(szParti al, szBuffer);
PostMessage(m_t hishWnd, WM_USER+1, 0, (LPARAM)szParti al);
}

PostMessage is platofrm dependent but it is not particulalry relevant
to this problem. It is just a mechanism to pass a message to another
thread in Windows.

Hello

I am doing this in a worker thread:

char* szPartial = new char[strlen(szBuffer )+1];
if (szPartial)
{
lstrcpy(szParti al, szBuffer);
PostMessage(m_t hishWnd, WM_USER+1, 0, (LPARAM)szParti al);
}

PostMessage is platofrm dependent but it is not particulalry relevant
to this problem. It is just a mechanism to pass a message to another
thread in Windows.

In the thread passed to, I do this:

// [lParam is the variable name of the dxPartial passed].
char* sz = reinterpret_cas t<char*>(lParam );
std::string str = sz;
delete [] sz;

Get an assert on the delete [] sz; - debug msg is:
DAMAGE: after Normal block (#56) at 0x008C4570

But why? What am I doing wrong?

Angus wrote:

Hello

I am doing this in a worker thread:

char* szPartial = new char[strlen(szBuffer )+1];
if (szPartial)
{
lstrcpy(szParti al, szBuffer);
PostMessage(m_t hishWnd, WM_USER+1, 0, (LPARAM)szParti al);
}

PostMessage is platofrm dependent but it is not particulalry relevant
to this problem. It is just a mechanism to pass a message to another
thread in Windows.

In the thread passed to, I do this:

// [lParam is the variable name of the dxPartial passed].
char* sz = reinterpret_cas t<char*>(lParam );
std::string str = sz;
delete [] sz;

Get an assert on the delete [] sz; - debug msg is:
DAMAGE: after Normal block (#56) at 0x008C4570

But why? What am I doing wrong?

Are you sure a pointer would fit into an LPARAM?
Perhaps sizeof(char*) sizeof(LPARAM)?

Other than that, I would try printing the adress just
before delete[] and compare it with the address obtained
by new, to make sure they are in fact the same.

HTH,
- J.- Hide quoted text -

- Show quoted text -

On 13 Feb, 11:03, Jacek Dziedzic
<jacek.dziedzic .n.o.s.p....@gm ail.comwrote:

Angus wrote:

Hello

I am doing this in a worker thread:

char* szPartial = new char[strlen(szBuffer )+1];
if (szPartial)
{
lstrcpy(szParti al, szBuffer);
PostMessage(m_t hishWnd, WM_USER+1, 0, (LPARAM)szParti al);
}

PostMessage is platofrm dependent but it is not particulalry relevant
to this problem. It is just a mechanism to pass a message to another
thread in Windows.

In the thread passed to, I do this:

// [lParam is the variable name of the dxPartial passed].
char* sz = reinterpret_cas t<char*>(lParam );
std::string str = sz;
delete [] sz;

Get an assert on the delete [] sz; - debug msg is:
DAMAGE: after Normal block (#56) at 0x008C4570

But why? What am I doing wrong?

Are you sure a pointer would fit into an LPARAM?
Perhaps sizeof(char*) sizeof(LPARAM)?

Other than that, I would try printing the adress just
before delete[] and compare it with the address obtained
by new, to make sure they are in fact the same.

HTH,
- J.- Hide quoted text -

- Show quoted text -

If I do the passing of data using a buffer - available to both threads
it works fine. so the amount of data is not the problem. But using
buffers, I get issues of buffers being overwritten if you send lots of
messages. If I remove the delete [] sz; it all works and the correct
data is passed. If I examine the text it is the same both ends.
LPARAM is an unsigned long. On my system sizeof(LPARAM) is 4,
sizeof(char*) is 4.

Hello

I am doing this in a worker thread:

char* szPartial = new char[strlen(szBuffer )+1];
if (szPartial)
{
lstrcpy(szParti al, szBuffer);
PostMessage(m_t hishWnd, WM_USER+1, 0, (LPARAM)szParti al);

}

PostMessage is platofrm dependent but it is not particulalry relevant
to this problem. It is just a mechanism to pass a message to another
thread in Windows.

>
In the thread passed to, I do this:

// [lParam is the variable name of the dxPartial passed].
char* sz = reinterpret_cas t<char*>(lParam );
std::string str = sz;
delete [] sz;

Get an assert on the delete [] sz; - debug msg is:
DAMAGE: after Normal block (#56) at 0x008C4570