QGL setFormat

I've subclassed QGLWidget to make my own OpenGL rendering context. I've been having wierd issues when testing the .exe on other computers, though, so I've tried to explicitly set the OpenGL version to 3.1 in the constructor:

Code:

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glWidget::glWidget(QWidget *parent) :
    QGLWidget(parent)
{
    QGLFormat newFormat;
    newFormat.setVersion(3,1);
    glWidget::context()->setFormat(newFormat); //error here
    glWidget::setMouseTracking(true);
}

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On the line that says "error here", I'm getting the following:

Code:

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C:\Qt\qtcreator-2.5.2\project\1KEdit\glwidget.cpp:15: error: C2662: 'QGLContext::setFormat' : cannot convert 'this' pointer from 'const QGLContext' to 'QGLContext &'

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I've tried rearranging it inside the constructor, but I'm always getting one error or another. I took the answer to this question as an example: http://stackoverflow.com/questions/5...get-at-runtime

How do I properly use setFormat?