goocanvasmm: problem on accessing cairo matrix

[David Davies <David questans co uk>]

I am trying to understand goocanvasmm by examining the examples in 
goocanvasmm-0.14.0
In the example called 'text' I have added two lines to window.cc as 
follows:

void ExampleWindow::update_label()
{
   cairo_matrix_t * pMatrix = m_text->property_transform(); // line A
   double x0 = pMatrix->x0; // line B

   std::stringstream str;
  ...
  etc

My aim is to output the components of the transform matrix so that I can 
understand what is happening to it.
The program compiles and links in CDT with no reported error.

If  I comment out line B, it runs OK and, as expected, gives the same 
output as the original example.
With line B however, the program terminates and outputs a <terminated> 
message without opening a window.
It does not report an error.

I should be very grateful  if anyone can throw any light on this.

DavidGSD