Re: function "&" for strings type cause memory problem.

["Alex R. Mosteo" <devnull@mailinator.com>]

bubble wrote:
> dear all:
> I have a project need mix 2 language (VB and Ada).
> 
> 
> VB do GUI  and monitor the real time quote then trigger kernel work.
> Ada with gnatcom to do kernel work (financial model pricing).
> 
> in the project, a code snip will raise storage_error excpeiton because I 
> combine 2  BIG string to 1 string.
> 
> I test the code snip and I get some problem in the statement, Nstring2 := 
> new String'(String1 & String2) .
> 
> if I compiling the code to stand alone execute file and enable pragma 
> Linker_Options ("-Wl,--stack=0x10000000");
> It both  passed.
> if I compiling it to DLL ,it pass test 1 and fail in test2
> 
>                                                     Test 1              | 
> Test 2
> -----------------------------------------------------------------------------------------------
> .exe with Linker_Options       |     Pass 
> Pass
> .exe without Liner_Options    |     Pass                                Fail
> .dll with Linker_Options         |    Pass 
> Fail
> .dll without Linker_Options    |    Pass 
> Fail
> 
> Test Environment
> ----------------------------------------------------------------------------------------------
> OS:Windows XP.
> memory :640 MB.
> VB: Microsoft Visual Basic 6
> gnatcom version: 1.4
> ada compiler: Gnat GPL 2005
> 
> 
> 
> I guess functin "&" for string type may have potential  problem in gnat 
> windows editions.
> does any body know the problem and give me some suggestion.
> thanks

This is just stack exhaustion. You can try either configuring your stack 
size big enough for any string in your system, or using Unbounded_String 
which uses memory from the heap. Though if you end converting them to 
regular String at some point I reckon you may have the same problem.


> Test Code
> --------------------------------------------------------------------------------------------------
> with Ada.Text_IO;
> Use Ada.Text_Io;
> 
> procedure test is
>    --pragma Linker_Options ("-Wl,--stack=0x10000000");
>    type access_string is access all String;
>    String1 : String := (1 .. 10_000_000 => 'a');
>    String2 : String := (1 .. 10_000_000 => 'b');
> 
> begin
>    declare
>       nString : access_string := null;
>    begin
>       nString:= new String (1 .. String1'Length + String2'Length);
>       nString.all (String1'First .. String2'Last) := String1;
>       nString.all ( String1'First + String2'First.. String1'First + 
> String2'Last):= String2;
>       Put_Line("Test 1 Passed");
>    Exception
>       When Others=>
>          Put_Line("Test 1 Fail");
>    end;
>    declare
>       Nstring2 : access_string := null;
>    begin
>       Nstring2 := new String'(String1 & String2);
>       Put_Line("Test 2 Passed ");
>    exception
>       when others =>
>          Ada.Text_IO.Put_Line ("Test 2 Fail");
>    end;
> end test; 
> 
>