The interface to C++ makes use of the following pragmas, which are primarily intended to be constructed automatically using a binding generator tool, although it is possible to construct them by hand.
Using these pragmas it is possible to achieve complete inter-operability between Ada tagged types and C++ class definitions. See Implementation Defined Pragmas, for more details.
pragma CPP_Class ([Entity =>] LOCAL_NAME)
The argument denotes an entity in the current declarative region that is declared as a tagged or untagged record type. It indicates that the type corresponds to an externally declared C++ class type, and is to be laid out the same way that C++ would lay out the type.
CPP_Class is currently obsolete. It is supported
for backward compatibility but its functionality is available
pragma CPP_Constructor ([Entity =>] LOCAL_NAME)
This pragma identifies an imported function (imported in the usual way
Import) as corresponding to a C++ constructor.
A few restrictions are placed on the use of the
in conjunction with subprograms subject to convention
attribute may be used neither on primitive operations of a tagged
record type with convention
CPP, imported or not, nor on
subprograms imported with pragma
In addition, C++ exceptions are propagated and can be handled in an
others choice of an exception handler. The corresponding Ada
occurrence has no message, and the simple name of the exception identity
Foreign_Exception. Finalization and awaiting dependent
tasks works properly when such foreign exceptions are propagated.
It is also possible to import a C++ exception using the following syntax:
LOCAL_NAME : exception; pragma Import (Cpp, [Entity =>] LOCAL_NAME, [External_Name =>] static_string_EXPRESSION);
External_Name is the name of the C++ RTTI symbol. You can then
cover a specific C++ exception in an exception handler.