Assuming you mean the FieldDef C++ object defined in the FGDBAPI include/Util.h, you would use the EnumRows::GetFields, Table::GetFields, or Row::GetFields request, and from there, iterate the array, accessing each FieldDef with it's getter methods:
fgdbError GetName(std::wstring& name) const;
fgdbError GetAlias(std::wstring& alias) const;
fgdbError GetType(FieldType& type) const;
fgdbError GetLength(int& length) const;
fgdbError GetIsNullable(bool& isNullable) const;
fgdbError GetGeometryDef(GeometryDef& geometryDef) const;
- V
