How to fix error LNK2019?

How to fix error LNK2019 when using videoInput.lib with OpenCv2.1?

• I am new in OpenCV and have some problems when using videoInput.lib,please help me.I am using winXP SP3+Cmake2.8.2+OpenCV 2.1+Visual Studio 2008.I have made every configuration and now OpenCv can be used when I am coding.I heard videoInput.lib has been included since OpenCV2.0 and I want to use it,so I tried codes below to quick test. // Test2.cpp : Defines the entry point for the console application. // #include "videoInput.h" #include "stdafx.h" #include "cv.h" #include "highgui.h" #include "cxcore.h" int main(int ,char * *) { int width=320; int height=240; IplImage *pRgb=cvCreateImage(cvSize(width,height), IPL_DEPTH_8U, 3); videoInput video; video.setupDevice(0, width, height); video.showSettingsWindow(0); while(1) { if(video.isFrameNew(0)) { video.getPixels(0, (unsigned char *)pRgb->imageData, false, true); //cvFlip(pRgb,NULL,1); char c=cvWaitKey(1); if(c==27) break; cvShowImage("Video", pRgb); } } } However when I build the codes,I got following error 1>------ Build started: Project: Test2, Configuration: Debug Win32 ------ 1>Compiling... 1>Test2.cpp 1>c:\opencv2.1\vc2008\include\opencv\cvcompat.h(803) : warning C4819: The file contains a character that cannot be represented in the current code page (936). Save the file in Unicode format to prevent data loss 1>Linking... 1>Test2.obj : error LNK2019: unresolved external symbol "public: __thiscall videoInput::~videoInput(void)" (??1videoInput@@QAE@XZ) referenced in function _main 1>Test2.obj : error LNK2019: unresolved external symbol "public: bool __thiscall videoInput::getPixels(int,unsigned char *,bool,bool)" (?getPixels@videoInput@@QAE_NHPAE_N1@Z) referenced in function _main 1>Test2.obj : error LNK2019: unresolved external symbol "public: bool __thiscall videoInput::isFrameNew(int)" (?isFrameNew@videoInput@@QAE_NH@Z) referenced in function _main 1>Test2.obj : error LNK2019: unresolved external symbol "public: void __thiscall videoInput::showSettingsWindow(int)" (?showSettingsWindow@videoInput@@QAEXH@Z) referenced in function _main 1>Test2.obj : error LNK2019: unresolved external symbol "public: bool __thiscall videoInput::setupDevice(int,int,int)" (?setupDevice@videoInput@@QAE_NHHH@Z) referenced in function _main 1>Test2.obj : error LNK2019: unresolved external symbol "public: __thiscall videoInput::videoInput(void)" (??0videoInput@@QAE@XZ) referenced in function _main 1>C:\Documents and Settings\SKSC\My Documents\Visual Studio 2008\Projects\Test2\Debug\Test2.exe : fatal error LNK1120: 6 unresolved externals 1>Build log was saved at "file://c:\Documents and Settings\SKSC\My Documents\Visual Studio 2008\Projects\Test2\Test2\Debug\BuildLog.htm" 1>Test2 - 7 error(s), 1 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== I have been googling for a long time but still can not find the solution,I am gonna mad.Does anyone know how to fix these problems? Thanks in advance.

• Answer:

  I think you still need to link with videoInput.lib, OpenCV uses videoInput.lib but it doesn't mean you can use all functions of videoInput.lib from OpenCV