CODEWITHSUNDEEP
c++pythonvisual-studioopencvcmake
Bull
Bull

Reputation: 11941

How to build OpenCV using Cmake/Visual Studio in Debug mode without Python debug library

I am trying to build OpenCv 2.4.7 from source on Windows 7 using Visual Studio 2012 (vc11). I have

In release mode, I can build all with no problem . However, when I attempt to build for debug mode I get the following error:

Error 2 error LNK1104: cannot open file 'python27_d.lib' C:\Users...\OpenCV\2.4.7\build\modules\python\LINK

I don't have a python27_d.lib, so I simply copied python27.lib to python27_d.lib, hoped for the best, and reran the cmake configuration (probably that last bit was pointless).

Now when I attempt to build I get these errors:

Error 1 error LNK2019: unresolved external symbol imp_Py_NegativeRefcount referenced in function "struct _object * cdecl pycvCreateHist(struct _object *,struct _object *,struct _object *)" (?pycvCreateHist@@YAPAU_object@@PAU1@00@Z) C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 2 error LNK2019: unresolved external symbol __imp_Py_Dealloc referenced in function "struct _object * cdecl pycvCreateHist(struct _object *,struct _object *,struct _object *)" (?pycvCreateHist@@YAPAU_object@@PAU1@00@Z) C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 3 error LNK2019: unresolved external symbol __imp_PyObject_DebugMalloc referenced in function "struct _object * cdecl pyopencv_VideoCapture_VideoCapture(struct _object *,struct _object *,struct _object *)" (?pyopencv_VideoCapture_VideoCapture@@YAPAU_object@@PAU1@00@Z) C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 4 error LNK2019: unresolved external symbol __imp_PyObject_DebugFree referenced in function "void cdecl Capture_dealloc(struct _object *)" (?Capture_dealloc@@YAXPAU_object@@@Z) C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 5 error LNK2019: unresolved external symbol _imp_Py_InitModule4TraceRefs referenced in function "struct _object * __cdecl init_cv(void)" (?init_cv@@YAPAU_object@@XZ) C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 6 error LNK2001: unresolved external symbol __imp_Py_RefTotal C:\Users...\OpenCV\2.4.7\build\modules\python\cv2.obj Error 7 error LNK1120: 6 unresolved externals C:\Users...\OpenCV\2.4.7\build\lib\Debug\cv2.pyd

Other than downloading the source for Python and making a debug build of it so I have a proper python27_d.lib (of which I think I have no other need), any ideas on how to solve this?

Upvotes: 2

Views: 6000

Answers (2)

LewisLau
LewisLau

Reputation: 11

find the pyconfig.h change

#ifdef _DEBUG 
# define Py_DEBUG 
#endif

to

#ifdef _DEBUG 
//# define Py_DEBUG 
#endif

chagne

# ifdef _DEBUG 
# pragma comment(lib,"python27_d.lib") 
# else 
# pragma comment(lib,"python27.lib") 
# endif /* _DEBUG */

to 

# ifdef _DEBUG 
# pragma comment(lib,"python27.lib") 
# else 
# pragma comment(lib,"python27.lib") 
# endif /* _DEBUG */

modify object.h 

#if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) 
#define Py_TRACE_REFS 
#endif

to

#if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) 
// #define Py_TRACE_REFS 
#endif

Upvotes: 1

pvl
pvl

Reputation: 194

According to the OpenCv website you need to switch the Visual Studio project to release after you have used CMake. http://docs.opencv.org/3.1.0/d5/de5/tutorial_py_setup_in_windows.html

This can be done by right clicking the solution and clicking configuration manager to access this setting.

I have tested this with Visual Studio 2015 Community, OpenCV 3.2.0 and python 3.6 (Anaconda)

Upvotes: 2

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