Problem with openCV compilation in Qt Creator

[mind_freak]

here is the code below:

const char *filename="C://OpenCV2.2//data//haarcascades//haarcascade_frontalface_alt.xml";
    cascade = ( CvHaarClassifierCascade* )cvLoad(filename,0,0,0);
    if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1;
        }
    storage=cvCreateMemStorage(0);
    capture=cvCaptureFromCAM(0);
   // assert( cascade && storage && capture );
    IplImage* frame= cvQueryFrame(capture);
    m_i=QImage(QSize(frame->width,frame->height),QImage::Format_RGB888);
    ui->frame->setMinimumSize(m_i.width(),m_i.height());
    ui->frame->setMaximumSize(ui->frame->minimumSize());
 
    m_opencvimg=cvCreateImageHeader(cvSize(m_i.width(),m_i.height()),8,3);
    m_opencvimg->imageData=(char*)m_i.bits();
 
    if(frame->origin== IPL_ORIGIN_TL)
        cvCopy(frame,m_opencvimg,0);
    else
        cvFlip(frame,m_opencvimg,0);
 
    cvCvtColor(m_opencvimg,m_opencvimg,CV_BGR2RGB);
 
    m_timer=new QTimer(this);
    connect(m_timer,SIGNAL(timeout()),this,SLOT(queryFrame()));
    m_timer->start(50);

const char *filename="C://OpenCV2.2//data//haarcascades//haarcascade_frontalface_alt.xml";
    cascade = ( CvHaarClassifierCascade* )cvLoad(filename,0,0,0);
    if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1;
        }
    storage=cvCreateMemStorage(0);
    capture=cvCaptureFromCAM(0);
   // assert( cascade && storage && capture );
    IplImage* frame= cvQueryFrame(capture);
    m_i=QImage(QSize(frame->width,frame->height),QImage::Format_RGB888);
    ui->frame->setMinimumSize(m_i.width(),m_i.height());
    ui->frame->setMaximumSize(ui->frame->minimumSize());

    m_opencvimg=cvCreateImageHeader(cvSize(m_i.width(),m_i.height()),8,3);
    m_opencvimg->imageData=(char*)m_i.bits();

    if(frame->origin== IPL_ORIGIN_TL)
        cvCopy(frame,m_opencvimg,0);
    else
        cvFlip(frame,m_opencvimg,0);

    cvCvtColor(m_opencvimg,m_opencvimg,CV_BGR2RGB);

    m_timer=new QTimer(this);
    connect(m_timer,SIGNAL(timeout()),this,SLOT(queryFrame()));
    m_timer->start(50);

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Error's i was getting while compiling this code:

C:/Users/mind_freak/facedetect-build-desktop/../facedetect/widget.cpp:15: error: returning a value from a constructor

i dont know i have given the correct path to the xml file but unable to load.

help me out of this....i am stuck with this....

thanks..

[stampede]

if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1;
        }

if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1;
        }

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Error message explains everything - you can't have a value return statement in constructor, this makes no sense. Remove the return -1 line.
Despite that, your constructor is doing a lot of work, this is not good, better create and call an initialization method, then in case of error you can return "false" or something.

[mcosta]

C:/Users/mind_freak/facedetect-build-desktop/../facedetect/widget.cpp:15: error: returning a value from a constructor

The problem is the piece of code

cascade = ( CvHaarClassifierCascade* )cvLoad(filename,0,0,0);
    if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1; // <---- This is the line 
        }

cascade = ( CvHaarClassifierCascade* )cvLoad(filename,0,0,0);
    if( !cascade )
        {
            fprintf( stderr, "ERROR: Could not load classifier cascade\n" );
            return -1; // <---- This is the line 
        }

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If the code is inside the constructor you cannot return a value