Re: How to get nice with GNAT?

["Björn Lundin" <b.f.lundin@gmail.com>]

On 2014-11-21 12:41, Natasha Kerensikova wrote:


> As a user, is there something I can do to improve the traceback
> representation on those platforms?
> Or is it completely in the hands of the GNAT packager/maintainer?
>

I run gnat on Aix/win32/linux32/64
and until recently, I tucked everything related
to stacktrace into a package Stacktrace.


package Stacktrace is
  procedure Tracebackinfo(E : Ada.Exceptions.Exception_Occurrence) ;
end Stacktrace;

used as

procedure bla is
...
...
exception
  when E: others =>
  Stacktrace.Tracebackinfo(E);
end ;

where i called
Ada.Exceptions.Exception_Name(E);
Ada.Exceptions.Exception_Message(E);
Ada.Exceptions.Exception_Information(E);

and output them

however, from Gnat GPL 2014 (64) and gnat fsf on debian Jessie
 (gnat 4.9 i think) the Tracebackinfo is not called anymore.

So my current workaround is to print those function directly
like

procedure bla is
...

exception
  when E: others =>
    declare
      Last_Exception_Name     : constant String  :=
Ada.Exceptions.Exception_Name(E);
      Last_Exception_Messsage : constant String  :=
Ada.Exceptions.Exception_Message(E);
      Last_Exception_Info     : constant String  :=
Ada.Exceptions.Exception_Information(E);
    begin
      Log(Last_Exception_Name);
      Log("Message : " & Last_Exception_Messsage);
      Log(Last_Exception_Info);
      Log("addr2line" & " --functions --basenames --exe=" &
           Ada.Command_Line.Command_Name & " " &
Stacktrace.Pure_Hexdump(Last_Exception_Info));
    end ;

end bla;



the function Pure_Hexdump strips away
everything before the first 0x in the string.


final output is like

2014-11-21 13:33:26.278 SQL.NOT_CONNECTED
2014-11-21 13:33:26.278 Message : Sql.Connect: Not_Connected
2014-11-21 13:33:26.278 Exception name: SQL.NOT_CONNECTED
Message: Sql.Connect: Not_Connected
Call stack traceback locations:
0x5be389 0x5cd93c 0x40c988 0x7fca95a8beab 0x40bab7

2014-11-21 13:33:26.278 addr2line --functions --basenames
--exe=/home/bnl/bnlbot/botstart/bot-1-0/target/bin/back_hitrate 0x5be389
0x5cd93c 0x40c988 0x7fca95a8beab 0x40bab7

and running addr2line gives

 addr2line --functions --basenames
--exe=/home/bnl/bnlbot/botstart/bot-1-0/target/bin/back_hitrate 0x5be389
0x5cd93c 0x40c988 0x7fca95a8beab 0x40bab7
sql__connect
sql.adb:432
_ada_back_hitrate
back_hitrate.adb:165
main
b~back_hitrate.adb:761
??
??:0
_start
??:?


A bit clumpsy but good enough for my _hobby_ projects.

--
Björn