I tried to integrate DirectMusic and Direct3D together by the samples, playAudio and progressive mesh. The PlayAudio was extracted for "included files", "variables", "initial function", "play sound function" and "close function" and attach to the Direct3D at suitable places; finally, the error seemed not from my code. Does any one could help me? Thanks! common files// dmutil.h dmutil.cpp dxutil.h dxutil.cpp Link library// d3dx8dt.lib d3d8.lib winmm.lib dxguid.lib d3dxof.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib including files// #define STRICT #include <stdio.h> #include <windows.h> #include <commdlg.h> #include "resource.h" #include <math.h> #include <time.h> #include <winbase.h> #include <stdlib.h> #include <basetsd.h> #include <commctrl.h> #include <tchar.h> #include <D3DX8.h> #include "D3DApp.h" #include "D3DFont.h" #include "D3DUtil.h" #include "DXUtil.h" #include <dmusicc.h> #include <dmusici.h> #include <dxerr8.h> #include "DMUtil.h" compiling// Linking... ProgressiveMesh.obj : error LNK2001: unresolved external symbol "long __stdcall DXTraceA(char *,unsigned long,long,char *,int)" (?DXTraceA@@YGJPADKJ0H@Z) dmutil.obj : error LNK2001: unresolved external symbol "long __stdcall DXTraceA(char *,unsigned long,long,char *,int)" (?DXTraceA@@YGJPADKJ0H@Z) dmutil.obj : error LNK2001: unresolved external symbol __imp__CoInitialize@4 dmutil.obj : error LNK2001: unresolved external symbol __imp__CoUninitialize@0 dmutil.obj : error LNK2001: unresolved external symbol __imp__CoCreateInstance@20 Debug/progressivemesh.exe : fatal error LNK1120: 4 unresolved externals Error executing link.exe. progressivemesh.exe - 6 error(s), 0 warning(s)