I've got a PDE file that declares a class in it that compiles fine under Arduino but not in Visual Micro. Turns out the pde preprocessor doen't like classes inside .pde files because it adds forward declarations for class members.  Take this example.pde

class A
{
public:
  virtual void foo() {}
};

void setup()
{
}

void loop()
{
}
 

This fails to compile with "virtual outside class declaration" because what is actually compiled adds a "virtual void foo();" above the class declaration. I'll submit this to codeplex but it is a gotcha that can emit any number of strange compiler errors, depending on what methods you have in your class. It confused the heck out of me because my class was actually a recursive template class definition which emitted a plethora of errors.

The solution is to define your classes in either a .h or .cpp file, which isn't preprocessed to add forward declarations.