Re: Problem passing In-Out parameter from C++ to Ada

["REH" <bogus@nowhere.net>]

"John Arnsparger" <johna42@houston.rr.com> wrote in message
news:mailman.93.1119636206.17633.comp.lang.ada@ada-france.org...
> Here is the code I'm using:
>
> //cpp_main.C
> #include <stdio.h>
> extern "C" {
>    void adainit (void);
>    void adafinal (void);
>    void var_test (int v);

try changing the above to:

void var_test(int* v);

> }
> int main ()
> {
>    adainit ();
>    int v1 = 3030;
>    printf ("In cpp_main, v1 = %d \n", v1);
>    var_test (v1);

var_test(&v1);

>    printf ("In cpp_main, after var_test call, v1 = %d \n", v1);
>    adafinal ();
> }
>
> -- simple_cpp_interface.ads
> package Simple_Cpp_Interface is
>    procedure Var_Test (V : in out Integer);
>    pragma Export (C, Var_Test, "var_test");
> end Simple_Cpp_Interface;
>
> -- simple_cpp_interface.adb
> with TEXT_IO;
> use  TEXT_IO;
> package body Simple_Cpp_Interface is
>
>    package IO is new TEXT_IO.INTEGER_IO(Integer);
>
>    procedure Var_Test (V : in out Integer) is
>    V1 : Integer := V;
>    begin
>       Put ("In Var_Test, V1= "); IO.Put ( V1 ); New_Line;
>    end Var_Test;
>
> end Simple_Cpp_Interface;
>
> -- Building it with the following commands:
>
> g++ -c cpp_main.C
> g++ -c simple_cpp_interface.adb
> gnatbind -n simple_cpp_interface
> gnatlink simple_cpp_interface -o cpp_main --LINK=g++ -lstdc++ cpp_main.o
> cpp_main
> In cpp_main, v1 = 3030
> Segmentation fault
>
>