Hi Tom, RTTI is some low-level C++ functionality to determine an objects type (roughly equivalent to `type(myobject)` in python). It can be enabled and disabled during compilation. Apparently it was disabled on your QGIS build.
The bad news: QGIS uses this information to determine which type of symbollayer is in use. The good news: This can be fixed, I've just fixed it in master . Please let me know if you need this backported and where to (so you can test). Matthias  https://github.com/qgis/QGIS/commit/8fa3127c66220ad338ea9a1b367b0d78c56c9067 On 10/16/2016 01:14 PM, Tom Chadwin wrote: > So RTTI is info about object data types at runtime? Is the print unable to > determine the symbollayer or symbollayerlist (or whatever the latter is) > type? Why? > > Obviously, my aim is not to print, but to use the data. However, the error > occurred before I used print to investigate the problem. > > Can anyone help? > > > > ----- > Buy Pie Spy: Adventures in British pastry 2010-11 on Amazon > -- > View this message in context: > http://osgeo-org.1560.x6.nabble.com/Access-violation-no-RTTI-data-tp5290830p5290885.html > Sent from the Quantum GIS - Developer mailing list archive at Nabble.com. > _______________________________________________ > Qgis-developer mailing list > Qgisemail@example.com > List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer > _______________________________________________ Qgis-developer mailing list Qgisfirstname.lastname@example.org List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer