How to create Visit Function for ProDrawingDimensionVisit()

That's how your callback (visitaction) might look like: 

ProError CollectDrawingDimensions(
 ProDimension *dimension, ProError /*status*/, ProAppData data)
{
 static_cast<vector<ProDimension>*>(data)->push_back(*dimension);

 return PRO_TK_NO_ERROR;
}

Use it like this:

std::vector<ProDimension> vecDrwDimensions;
ProError err = ProDrawingDimensionVisit(
 Drawing,
 PRO_DIMENSION,
 CollectDrawingDimensions,
 NULL,
 (ProAppData)&vecDrwDimensions);