CODEWITHSUNDEEP
c++segmentation-faultada
jski
jski

Reputation: 715

C++ to Ada with pointers and exceptions

I'm interviewing potential software engineering candidates and would like a translation into Ada of this piece of C++ code:

#include <iostream>

int main(int argc, char *argv[])
{
  int *W = NULL;
  try { *W = 3; }
  catch (...) { std::cout << "default exception"; }
}

As with the C++ code, I want the Ada code to result in "terminated by signal SIGSEGV".

BTW, I'm using the latest GNAT (GNAT 9.1.1 20190503 (Red Hat 9.1.1-1) )

Upvotes: 0

Views: 384

Answers (3)

jski
jski

Reputation: 715

Having spent years working with C++ and only just recently Ada, I believe if given a choice of a plane with its avionics written in Ada or one with its avionics written C++, I'd jump on the Ada plane. I've watched C++ grow with every release of a new standard ever more complex and, consequently, ever more unmanageable.

Ada is simple (compared to C++) and hence, much easier to manage. I'm not sure what C++ advantages exist vs Ada? None is the obvious answer.

It's a shame the DoD completely mismanaged Ada when it was first introduced. If they'd only paid Borland to develop a "Turbo Ada" and then given it away.

Upvotes: 1

OCTAGRAM
OCTAGRAM

Reputation: 706

with Ada.Wide_Wide_Text_IO; use Ada.Wide_Wide_Text_IO;
with System;

procedure SigSegV is
   W : Integer with Import, Address => System.Null_Address;
begin
   W := 3;
exception
   when others =>
      Put_Line ("default exception");
end SigSegV;

SIGSEGV is converted to Standard.Storage_Error

Upvotes: 2

Fr&#233;d&#233;ric Praca
Fr&#233;d&#233;ric Praca

Reputation: 1641

The corresponding code in Ada would be something like

with Ada.Text_IO; use Ada.Text_IO;

procedure SigSegV is
   type Int_Ptr is access Integer;

   W : Int_Ptr := null;
begin
   W.all := 3;
exception
   when others =>
      Put_Line ("default exception");
end SigSegV;

But it doesn't trigger a SIGSEGV signal and you get the message as expected. Moreover, the compiler already warned you :

sigsegv.adb:8:04: warning: null value not allowed here
sigsegv.adb:8:04: warning: "Constraint_Error" will be raised at run time

So I am not sure that you can get the same behaviour than in C++ with Ada code... Apart from calling C++ from Ada :D

Upvotes: 6

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