opencv error: Null pointer(Null filename) in unknown function with facedetect. cpp

OpenCV includes face detection sample code. I tried to use facedetect.cpp from OpenCV 2.2 library in my application. However, I happened to a runtime problem

OpenCV error: Null pointer(Null filename) in unknown function, file..\..\..\..\ocv\opencv\modules\core\src\persistence.cpp,line 2571

I googled 开发者_开发百科it and found lots of people ran across this problem, but without a good solution. This problem happened when code load .xml file. My solution is here:

const char *cascadeNameChar=cascadeName.c_str();
const char *nestedCascadeNameChar=nestedCascadeName.c_str();
......
if( !cvLoad( nestedCascadeNameChar ) )
if(!cascade.load(cascadeName))

Then it works for me. I run it on Visual Studio 2008.

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Mates, I have figured out this problem. I used opencv2.2+Visual Studio 2008 when I happened to this problem. The Opencv2.2 is binary version I downloaded from http://sourceforge.net that have been compiled with respect to vc2010. I just now downloaded vc2010 and try my application with facedetect.cpp from opencv2.2 on it. It works! The runtime error with persistence.cpp is gone.