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27.2 Generating bindings for C++ headers

Generating bindings for C++ headers is done using the same options, always with the g++ compiler.

In this mode, C++ classes will be mapped to Ada tagged types, constructors will be mapped using the CPP_Constructor pragma, and when possible, multiple inheritance of abstract classes will be mapped to Ada interfaces (See Interfacing to C++, for additional information on interfacing to C++).

For example, given the following C++ header file:

     

class Carnivore { public: virtual int Number_Of_Teeth () = 0; }; class Domestic { public: virtual void Set_Owner (char* Name) = 0; }; class Animal { public: int Age_Count; virtual void Set_Age (int New_Age); }; class Dog : Animal, Carnivore, Domestic { public: int Tooth_Count; char *Owner; virtual int Number_Of_Teeth (); virtual void Set_Owner (char* Name); Dog(); };

The corresponding Ada code is generated:

     

package Class_Carnivore is type Carnivore is limited interface; pragma Import (CPP, Carnivore); function Number_Of_Teeth (this : access Carnivore) return int is abstract; end; use Class_Carnivore; package Class_Domestic is type Domestic is limited interface; pragma Import (CPP, Domestic); procedure Set_Owner (this : access Domestic; Name : Interfaces.C.Strings.chars_ptr) is abstract; end; use Class_Domestic; package Class_Animal is type Animal is tagged limited record Age_Count : aliased int; end record; pragma Import (CPP, Animal); procedure Set_Age (this : access Animal; New_Age : int); pragma Import (CPP, Set_Age, "_ZN6Animal7Set_AgeEi"); end; use Class_Animal; package Class_Dog is type Dog is new Animal and Carnivore and Domestic with record Tooth_Count : aliased int; Owner : Interfaces.C.Strings.chars_ptr; end record; pragma Import (CPP, Dog); function Number_Of_Teeth (this : access Dog) return int; pragma Import (CPP, Number_Of_Teeth, "_ZN3Dog15Number_Of_TeethEv"); procedure Set_Owner (this : access Dog; Name : Interfaces.C.Strings.chars_ptr); pragma Import (CPP, Set_Owner, "_ZN3Dog9Set_OwnerEPc"); function New_Dog return Dog; pragma CPP_Constructor (New_Dog); pragma Import (CPP, New_Dog, "_ZN3DogC1Ev"); end; use Class_Dog;