Call a foreign-language function

Call a foreign-language function
You are encouraged to solve this task according to the task description, using any language you may know.

Show how a foreign language function can be called from the language. As an example, take C language. Create a string containing "Hello World!" of the string type typical to the language. Pass the string content to C's strdup. The content can be copied if necessary. Get the result from strdup and print it using language means. Do not forget to free the result of strdup (allocated in the heap).

Notes

• It is not mandated if the C run-time library is to be loaded statically or dynamically. You are free to use either way.
• C++ and C solutions can take some other language to communicate with.

Ada

Ada provides standard interfaces to C, C++, Fortran and Cobol. Other language interfaces can be provided as well, but are not mandatory. Usually it is possible to communicate to any language that supports calling conventions standard to the OS (cdecl, stdcall etc). <lang Ada> with Ada.Text_IO; use Ada.Text_IO; with Interfaces.C; use Interfaces.C; with Interfaces.C.Strings; use Interfaces.C.Strings;

procedure Test_C_Interface is

  function strdup (s1 : Char_Array) return Chars_Ptr;
  pragma Import (C, strdup, "_strdup");

  S1 : constant String := "Hello World!";
  S2 : Chars_Ptr;

begin

  S2 := strdup (To_C (S1));
  Put_Line (Value (S2));
  Free (S2);

end Test_C_Interface; </lang>

Common Lisp

Library: CFFI

<lang lisp>CL-USER> (let* ((string "Hello World!")

               (c-string (cffi:foreign-funcall "strdup" :string string :pointer)))
          (unwind-protect (write-line (cffi:foreign-string-to-lisp c-string))
            (cffi:foreign-funcall "free" :pointer c-string :void))
          (values))

Hello World!

No value</lang>