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Posted 31 Jan 2000

Automatic Tab Bar for MDI Frameworks

, 3 Jan 2003
A dockable bar containing a tabbed list of open windows
// TraceWin Copyright 1995-1999 Paul DiLascia
// If this program works, it was written by Paul DiLascia.
// If not, I don't know who wrote it.
// NOTE: If you're using PixieLib, you don't need to include this file.
// It's already included by the library.
// ***************************************************************************
// TraceWin is a tool that displays MFC diagnostic (afxDump, TRACE) output
// in the window of the TraceWin applet.
// To use TraceWin, you must #include this file somewhere in your main program
// file (typically where you implement your CWinApp). Since this file contains
// code, you should #include it in only once--i.e. NOT in StdAfx.h--or you'll
// get multiply-defined symbol errors in the linker. This file contains an
// auto-initializing static variable that works in most cases; but you may miss
// some TRACE output from constructors of static objects. If so, you can
// manually call PxlTraceInit before your first TRACE call.
// To see the output, you also need the TraceWin applet, TraceWin.exe, which
// you can download
// ***************************************************************************
#ifdef _DEBUG

// Window class name used by the main window of the TRACEWIN applet.
#define TRACEWND_CLASSNAME _T("TraceWin TRACE Window")
#define OLDTRACEWND_CLASSNAME _T("MfxTraceWindow") // backwards compat

// ID sent as COPYDATASRUCT::dwData to identify the WM_COPYDATA message
// as coming from an app using TraceWin.

// CFileTrace is a CFile that "writes" to the trace window
class CFileTrace : public CFile {
	CFileTrace() { m_strFileName = _T("Mfx File Tracer"); }
	static BOOL autoInit;
	virtual void Write(const void* lpBuf, UINT nCount);
	static  BOOL Init();	

// Override to write to TraceWin applet instead of file.
void CFileTrace::Write(const void* lpBuf, UINT nCount)
	if (!afxTraceEnabled)
		return;	// MFC tracing not enabled

	if (hTraceWnd==NULL)
		hTraceWnd = ::FindWindow(OLDTRACEWND_CLASSNAME, NULL);
	if (hTraceWnd) {
		// Found Trace window: send string with WM_COPYDATA
		// Must copy to make me the owner of the string; otherwise
		// barfs when called from MFC with traceMultiApp on
		static char mybuf[1024];

#ifdef _UNICODE
		BOOL bDefCharUsed;
			-1, mybuf, 1024, NULL, &bDefCharUsed);
		memcpy(mybuf, lpBuf, nCount);

		cds.cbData = nCount;
		cds.lpData = mybuf;
		CWinApp* pApp = AfxGetApp();
		HWND hWnd = pApp ? pApp->m_pMainWnd->GetSafeHwnd() : NULL;
		::SendMessage(hTraceWnd, WM_COPYDATA, (WPARAM)hWnd, (LPARAM)&cds);
	// Also do normal debug thing

// Initialize tracing. Replace global afxDump.m_pFile with CFileTrace object.
// In VC 5.0, you shouldn't need to call this, since it's called from an
// auto-initializing static object autoInit below. But if you don't see
// any TRACE output in the TraceWin window, you should try calling
// PxlTraceInit any time before your first TRACE message.
BOOL CFileTrace::Init()
	if (afxDump.m_pFile==NULL) {
		// Initialize tracing: replace afxDump.m_pFile w/my own CFile object
		// It's important to allocate with "new" here, not a static object,
		// because CFileTrace is virtual--i.e., called through a pointer in
		// the object's vtbl--and the compiler will zero out the virtual
		// function table with a NOP function when a static object
		// goes out of scope. But I want my CFileTrace to stay around to
		// display memory leak diagnostics even after all static objects
		// have been destructed. So I allocate the object with new and
		// never delete it. I don't want this allocation to itself generate
		// a reported memory leak, so I turn off memory tracking before I
		// allocate, then on again after.
		BOOL bEnable = AfxEnableMemoryTracking(FALSE);
		afxDump.m_pFile = new CFileTrace;
		return TRUE;
	return FALSE;

// This object does nothing but call CFileTrace::Init, so all you have to
// do is #include this file. Because afxDump is defined in a module with
// #pragma init_seg(lib)
// afxDump gets initialized before the "user" segment which is where your
// app (and autoInit) is by default. If you need to use init_seg(lib),
// or you have other objects whose constructors call TRACE that get
// initialized before CFileTrace::bInitialized, you will have to call
// CFileTrace::Init yourself, before your first TRACE statement.
BOOL CFileTrace::autoInit = CFileTrace::Init();

// This symbol defined so you can call it and have it
// compile to nothing in non-debug build
#define PxlTraceInit() CFileTrace::Init();


#define PxlTraceInit()

#endif // _DEBUG

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About the Author

Paul Selormey
Japan Japan
Systems Engineer

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