Random crash in iterator

[Nitorami]

What's going on here ?

Code: Pascal  [Select][+][-]

1. program mist4;
2.  
3. var TiF: double;
4.  
5. begin
6.   for Tif in [0.1, 0.2, 0.5, 1.0, 10.0] do begin
7.     writeln (TiF);
8.   end;
9. end.
10.  

Output:

Running "c:\temp\mist4.exe 7"
 1.0000000000000001E-001
 2.0000000000000001E-001
 0.0000000000000000E+000
Runtime error 205 at $0040164C
  $0040164C  main,  line 5 of C:/Users/e09neum0/Documents/PAS/GX1/mist4.pas
  $0040A727

Sometimes runtime error 205, sometimes 207, sometimes division by zero or other. Depends on the numbers given.  Not sure whether I can use floating point values here, but if not, the compiler should throw an error.

FPC 3.3.2, i386-win32.

[Fibonacci]

FPC 3.3.2

Where did you get that?

[Eugene Loza]

Works for me without any issues

[Martin_fr]

It seems 32 bit only...

IIRC there is an issue that if you have an inlined list/array, the type is determined by the FIRST element ONLY. And all others are truncated or otherwise handled faulty.
E.g. a list of shortstring, will take the length of the first string, and cut all others.

I don't know, if your test hits this issue.

[Nitorami]

@Fibonacci: Sorry, typo. I meant 3.2.2.

@martin_fr: ok but all elements are double and of same size, so I can't see the problem ?

[YiannisKam]

There is something wrong here (FPC 3.2.2, Windows 10 64bit)

Code: Pascal  [Select][+][-]

1. program ForIn;
2.  
3. {$mode objfpc}{$H+}
4.  
5. var
6.   d: double;
7.  
8. begin
9.   for d in [0.1, 0.2, 0.5, 1.0, 10.0] do
10.     WriteLn(d);
11.   ReadLn;
12. end.

Output:
1.0000000000000001E-001
 2.0000000000000001E-001
 5.2220990168285998E-315
 5.2635442471208903E-315
 5.3982412455708344E-315

And if:

Code: Pascal  [Select][+][-]

1. program ForIn;
2.  
3. {$mode objfpc}{$H+}
4.  
5. var
6.   d: double;
7.  
8. begin
9.   for d in [0.1, 0.2, 0.5, 1.0, 10.0] do
10.     WriteLn(d:0:1);
11.   ReadLn;
12. end.

Output:
0.1
0.2
0.0
0.0
0.0

[Nitorami]

THIS works 
So it has to do with the size of elements....

Code: Pascal  [Select][+][-]

1. program mist4;
2. var TiF: double;
3.  
4. begin
5.   for Tif in [double(0.1), double(0.2), double(0.5), double(1.0), double(10.0)] do begin
6.     writeln (TiF);
7.   end;
8. end.

Running "c:\temp\mist4.exe 7"
 1.0000000000000001E-001
 2.0000000000000001E-001
 5.0000000000000000E-001
 1.0000000000000000E+000
 1.0000000000000000E+001

[Thaddy]

Code: Bash  [Select][+][-]

1. 0.1000
2. 0.2000
3. 0.5000
4. 1.0000
5. 10.0000

based on

Code: Pascal  [Select][+][-]

1. var TiF: double;
2. begin
3.   for Tif in [0.1, 0.2, 0.5, 1.0, 10.0] do
4.     writeln (TiF:4:4);
5. end.

On Windows11/64 trunk 3.3.1 from this week.

[Nitorami]

Please try something like this

Code: Pascal  [Select][+][-]

1. for Tif in [-3, 0.2, 0.5, 1.0, 10.0]

I don't have trunk but it fails in Lazarus 2.2.6 (x64). It seems the first element is parsed as integer and than the rest goes wrong.

-3.0000000000000000E+000
-1.0200000000000000E+002
 0.0000000000000000E+000
 0.0000000000000000E+000
 0.0000000000000000E+000

[Bart]

Please try something like this

Code: Pascal  [Select][+][-]

1. for Tif in [-3, 0.2, 0.5, 1.0, 10.0]

Fixed in fpc main.
Now all that rests is to test with fpc 3.2 fixes branch to see wether this was merged.

Bart

[Thaddy]

I don't have trunk but it fails in Lazarus 2.2.6 (x64). It seems the first element is parsed as integer and than the rest goes wrong.

It is not related to Lazarus, but to FPC and it is fixed in trunk, nowadays called main for some reason.(FPC trunk, not Lazarus trunk)
Such issues should always refer to the compiler version, not a Lazarus version.

[VisualLab]

Test in Windows 10 64-bit, Lazarus 3.0 64-bit (FPC 3.2.2):

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls;
9.  
10. type
11.   {TForm1}
12.   TForm1 = class(TForm)
13.     Button1: TButton;
14.     Memo1: TMemo;
15.     procedure Button1Click(Sender: TObject);
16.   end;
17.  
18.   TNumberArray = array [1..5] of Double;
19.  
20. var
21.   Form1: TForm1;
22.  
23. implementation
24.  
25. {$R *.lfm}
26.  
27. {TForm1}
28.  
29. procedure TForm1.Button1Click(Sender: TObject);
30. const
31.   ConstNumbers: array [1..5] of Double = (0.1, 0.2, 0.5, 1.0, 10.0);
32. var
33.   TiF: Double;
34.   VarNumbers: TNumberArray;
35. begin
36.   Memo1.Lines.Clear;
37.   {numbers as literals}
38.   Memo1.Lines.Add('numbers as literals:');
39.   for Tif in [0.1, 0.2, 0.5, 1.0, 10.0] do
40.    begin
41.     Memo1.Lines.Add(Tif.ToString);
42.    end;
43.   Memo1.Lines.Add('---');
44.   {numbers in constant}
45.   Memo1.Lines.Add('numbers in constant:');
46.   for Tif in ConstNumbers do
47.    begin
48.     Memo1.Lines.Add(Tif.ToString);
49.    end;
50.   Memo1.Lines.Add('---');
51.   {numbers in variable}
52.   Memo1.Lines.Add('numbers in variable:');
53.   VarNumbers[1] := 0.1;
54.   VarNumbers[2] := 0.2;
55.   VarNumbers[3] := 0.5;
56.   VarNumbers[4] := 1.0;
57.   VarNumbers[5] := 10.0;
58.   for Tif in VarNumbers do
59.    begin
60.     Memo1.Lines.Add(Tif.ToString);
61.    end;
62. end;
63.  
64. end.

Results in attachment (screenshot).

[paweld]

@VisualLab: Windows 10 64-bit, Lazarus trunk + FPC 3.2-fixes (32 and 64-bit)

Code: [Select]

numbers as literals:
0,1
0,2
0,5
1
10
---
numbers in constant:
0,1
0,2
0,5
1
10
---
numbers in variable:
0,1
0,2
0,5
1
10