FIX: Assertion Failed, Line 505 of Sockcore.cpp (139693)
The information in this article applies to:
- The Microsoft Foundation Classes (MFC), when used with:
- Microsoft Visual C++ for Windows, 16-bit edition 1.52
- Microsoft Visual C++, 32-bit Editions 2.1
- Microsoft Visual C++, 32-bit Editions 2.2
This article was previously published under Q139693 SYMPTOMS
An MFC application that uses the socket classes fails with a message
similar to the following:
In MFC 3.1 or 3.2, the assertion appears as:
Assertion Failed: <app name>: File sockcore.cpp, Line 505
In MFC 2.52, the assertion appears as:
Assertion Failed: <app name>: File sockcore.cpp, Line 484
CAUSE
When all sockets are closed, the socket handle maps are emptied and the
socket notification window is destroyed.
MFC maintains an auxiliary queue of socket notification messages. If any
messages remain in this queue when the last socket is closed, then this
assertion failure will occur when any new sockets are opened and an attempt
is made to process these left-over notifications.
RESOLUTION
Purge the auxiliary queue of all messages when the last socket is closed.
In this context, last does not mean previous; it means the socket that was
closed, leaving no sockets open for that thread.
This problem can be remedied by overriding the CAsyncSocket::Close member
function in your CAsyncSocket-derived or CSocket-derived class. The
following implementation of this override will take care of the problem:
void CMySocket::Close()
{
// If Deriving from CSocket, then use:
CSocket::Close();
// Otherwise, use:
// CAsyncSocket::Close();
AFX_THREAD_STATE* pThreadState = AfxGetThreadState();
if (pThreadState->m_mapSocketHandle.IsEmpty())
{ // **** LAST SOCKET ****
while (!pThreadState->m_listSocketNotifications.IsEmpty())
delete pThreadState->m_listSocketNotifications.RemoveHead();
pThreadState->m_listSocketNotifications.RemoveAll();
}
}
To handle the case where a socket object is deleted before Close is called,
also override the virtual destructor to make sure the correct version of
Close is called:
CMySocket::~CMySocket()
{
if (m_hSocket != INVALID_SOCKET)
Close();
}
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed
at the beginning of this article. This problem was corrected in the version
of MFC that ships with Microsoft Visual C++, 32-bit Edition, version 4.0.
| Modification Type: | Major | Last Reviewed: | 12/1/2003 |
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| Keywords: | kbBug kbfix kbNoUpdate kbVC400fix kbWinsock KB139693 |
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