DS-4000系列板卡SDK and Demo Version 5.1 中的错误
错误定位
1，工程名字：Src/NetDemoSource/NetServerDemo 工程名: HKVision。服务器端的demo。
2，文件和错误定位：
1）中断出现在HKVision.cpp中86行的语句： int nResponse = dlg.DoModal();
BOOL CHKVisionApp::InitInstance() { if (!AfxSocketInit()) { AfxMessageBox(IDP_SOCKETS_INIT_FAILED); return FALSE; } AfxEnableControlContainer(); // Standard initialization // If you are not using these features and wish to reduce the size // of your final executable, you should remove from the following // the specific initialization routines you do not need. #ifdef _AFXDLL Enable3dControls(); // Call this when using MFC in a shared DLL #else Enable3dControlsStatic(); // Call this when linking to MFC statically #endif int w = GetSystemMetrics(SM_CXSCREEN); int h = GetSystemMetrics(SM_CYSCREEN); if((w < 1024)||(h < 768)){ AfxMessageBox("You must set display resolution to 1024x768 or more in order to run the program/n"); return FALSE; } CHKVisionDlg dlg; m_pMainWnd = &dlg; RegisterLogRecordCallback(LogRecordFunc, &dlg); int nResponse = dlg.DoModal(); if (nResponse == IDOK) { // TODO: Place code here to handle when the dialog is // dismissed with OK } else if (nResponse == IDCANCEL) { // TODO: Place code here to handle when the dialog is // dismissed with Cancel } // Since the dialog has been closed, return FALSE so that we exit the // application, rather than start the application's message pump. return FALSE; }
2）调试跟踪到了HKVisionDlg.cpp中函数BOOL CHKVisionDlg::OnInitDialog()中语句：
if (!MP4_ServerStart(&videoinfo))
{
MessageBox("error","error",MB_OK);
}
具体位置在459行。
3）最终错误定位在函数：
int __cdecl StreamDirectReadCallback(ULONG channelNum,void *DataBuf,DWORD Length,int frameType,void *context)
该函数中的：
CHKVisionDlg *pMain = (CHKVisionDlg *)AfxGetMainWnd();
pMain->GetDlgItem(IDC_BPS)->SetWindowText((LPCTSTR)str);
错误分析：
MP4_ServerStart时候，调用回调函数StreamDirectReadCallback函数，估计（源码未公开）是专门开了一个线程调用StreamDirectReadCallback函数。在StreamDirectReadCallback函数中使用了AfxGetMainWnd()。而AfxGetMainWnd函数返回null，可以google “AfxGetMainWnd null” "AfxGetMainWnd 失效"。
http://topic.csdn.net/u/20100430/10/1FF4D768-E1A3-4B4D-8F77-0EFB2A3DFD08.html
解决方法：
将pMain作为全局的CHKVisionDlg*指针，初始化为NULL，在CHKVisionDlg::OnInitDialog 中，函数结尾处添加：
pMain = this;
最后再StreamDirectReadCallback中可以直接使用pMain了。。。
后记
错误定位最为痛苦。步骤1，到步骤2，再到步骤3的跟踪很需要想象力，直接F11根本跟不过去，一个下午才解决。所以写出来~，跟大家分享~