tracewin.h

学习MFC的好东西

////////////////////////////////////////////////////////////////
// TRACEWIN Copyright 1995 Microsoft Systems Journal. 
// If this program works, it was written by Paul DiLascia.
// If not, I don't know who wrote it.
//
// TRACEWIN header file. Include this file in any application you want to
// use TRACEWIN. #include-ing this file will make diagnostic output go
// to the TRACEWIN applet if it is running.
//
// You should only #include this file one place in your app.
// 
// You must also call CMfxTrace::Init as the first thing in your app's 
// InitInstance function.
//
// NOTE: The implementation was changed 10-12-95 to use WM_COPYDATA instead
// of atoms. This differs from the code in the orignal October 1995 issue
// of MSJ. Also note the name of this file is changed to TRACEWIN.H.

#define TRACEWND_CLASSNAME "MfxTraceWindow"

// This ID is sent as COPYDATASRUCT::dwData to identify the WM_COPYDATA
// message as coming from an app using TRACEWIN. 
// It's "twin" encoded as a long.
//
#define ID_COPYDATA_TRACEMSG MAKELONG(MAKEWORD('t','w'),MAKEWORD('i','n'))

#ifdef _DEBUG

class CMfxTrace : public CFile {
	static CMfxTrace theTracer;	// one-and-only tracing object
	CMfxTrace();						// private constructor
public:
	virtual void Write(const void* lpBuf, UINT nCount);
	static void Init();
};

// The one and only tracer
CMfxTrace CMfxTrace::theTracer;

//////////////////
// Constructor installs itself as file afxDump
//
CMfxTrace::CMfxTrace()
{
	ASSERT(this==&theTracer);
}

/////////////////
// Initialize tracing. Replace global afxDump.m_pFile with me.
//
void CMfxTrace::Init()
{
	if (afxDump.m_pFile == NULL) {
		afxDump.m_pFile = &theTracer;
	} else if (afxDump.m_pFile != &theTracer) {
		TRACE("afxDump is already using a file: TRACEWIN not installed.\n");
	}
}

//////////////////
// Override Write function to Write to TRACEWIN applet instead of file.
//
void CMfxTrace::Write(const void* lpBuf, UINT nCount)
{
	if (!afxTraceEnabled)
		return;

	CWnd *pTraceWnd = CWnd::FindWindow(TRACEWND_CLASSNAME, NULL);
	if (pTraceWnd) {
		// Found Trace window: send string with WM_COPYDATA
		//
		COPYDATASTRUCT cds;
		cds.dwData = ID_COPYDATA_TRACEMSG;
		cds.cbData = nCount;
		cds.lpData = (void*)lpBuf;
		pTraceWnd->SendMessage(WM_COPYDATA, 
			(WPARAM)AfxGetApp()->m_pMainWnd->GetSafeHwnd(), 
			(LPARAM)&cds);

	} else {
		// No trace window: do normal debug thing
		//
		::OutputDebugString((LPCSTR)lpBuf);	
	}
}

#endif // _DEBUG