Stopping the debugger under a certain condition

[zoltanleo]

Hi guys. I need your help.

In my application, in each iteration loop, I parse the string and remove the "extra" characters, e.g.:

Code: Pascal  [Select][+][-]

1.           //get position #10 in the line
2.           LineEndingPos_10:= Pos(#10,Buffer);
3.  
4.           repeat {until LineEndingPos_10 = 0;}
5.             case LineEndingPos_10 of
6.               0:
7.                 begin
8.                   {I need to stop the debugger here...}
9.                   BufferStg:= BufferStg + Buffer;
10.                 end;
11.               1: //#10 at the beginning of the line
12.                 begin
13.                   Inc(StrCounter);
14.                   if Length(BufferStg) > 0 then
15.                   begin
16.                     //dump the buffer storage to memo ...
17.                     memoOutput.Lines.Add(Format(ConstFormatStr,[StrCounter,'B',BufferStg]));{B}
18.                     memoOutput.SelStart:= UTF8Length(memoOutput.Text);
19.                   end;
20.                   Application.ProcessMessages;
21.  
22.                   //clear the storage buffer
23.                   BufferStg:='';
24.  
25.                   //clip the first character #10(LF) from the buffer
26.                   Delete(Buffer,1,1);
27.  
28.                   //... and continue the cycle further
29.                 end
30.               else //#10(LF) in the middle or at the end of the buffer  
31.               ...
32.  

The total number of iteration cycles is more than 4400. An error can occur on a cycle with the number 2531, e.g.:

Code: Pascal  [Select][+][-]

1. 2528. {C}~ gbak:0 records written
2. 2529. {C}~ gbak:    writing index PK_TBL_LS_INFECTION_HIV
3. 2530. {C}~ gbak:    writing data for table TBL_LS_INFECTION_HIV
4. gbak:0 records written
5. 2531. {C}~ gbak:    writing index PK_TBL_LS_INFECTION_HERPES6
6. 2532. {C}~ gbak:    writing data for table TBL_LS_INFECTION_HERPES6

It will take a very long time if I press F8 2530 times.

Can I stop debugging under a certain condition, e.g. when the iteration counter reaches the number 2528?

[lucamar]

If you have any kind of counter (say, you¡'re using a for loop or increasing a "total" counter with each iteration) you can set a conditional breakpoint.

You can either use "Run -> Add breakpoint" and set the breakpoint properties or set a breakpoint with F5 and then edit its properties by using "View -> Debug Windows -> Breakpoints"

[RayoGlauco]

Surely there is a more elegant way to do it, but I usually add temporarily a counter and an extra instruction inside the loop:

Code: Pascal  [Select][+][-]

1. var
2.   loopcount: integer;
3. {...}
4. repeat
5.   ...
6.   if loopcount = 2531 then
7.     sleep(10);
8.   ...
9.  

Then, I set a breakpoint on sleep(10);

[zoltanleo]

@lucamar
thanks for the advice

Then, I set a breakpoint on sleep(10);

This is exactly what I wanted to hear. Thank you very much.

[valdir.marcos]

Hi guys. I need your help.

In my application, in each iteration loop, I parse the string and remove the "extra" characters, e.g.:

Code: Pascal  [Select][+][-]

1.           //get position #10 in the line
2.           LineEndingPos_10:= Pos(#10,Buffer);
3.  
4.           repeat {until LineEndingPos_10 = 0;}
5.             case LineEndingPos_10 of
6.               0:
7.                 begin
8.                   {I need to stop the debugger here...}
9.                   BufferStg:= BufferStg + Buffer;
10.                 end;
11.               1: //#10 at the beginning of the line
12.                 begin
13.                   Inc(StrCounter);
14.                   if Length(BufferStg) > 0 then
15.                   begin
16.                     //dump the buffer storage to memo ...
17.                     memoOutput.Lines.Add(Format(ConstFormatStr,[StrCounter,'B',BufferStg]));{B}
18.                     memoOutput.SelStart:= UTF8Length(memoOutput.Text);
19.                   end;
20.                   Application.ProcessMessages;
21.  
22.                   //clear the storage buffer
23.                   BufferStg:='';
24.  
25.                   //clip the first character #10(LF) from the buffer
26.                   Delete(Buffer,1,1);
27.  
28.                   //... and continue the cycle further
29.                 end
30.               else //#10(LF) in the middle or at the end of the buffer  
31.               ...

The total number of iteration cycles is more than 4400. An error can occur on a cycle with the number 2531, e.g.:

Code: Pascal  [Select][+][-]

1. 2528. {C}~ gbak:0 records written
2. 2529. {C}~ gbak:    writing index PK_TBL_LS_INFECTION_HIV
3. 2530. {C}~ gbak:    writing data for table TBL_LS_INFECTION_HIV
4. gbak:0 records written
5. 2531. {C}~ gbak:    writing index PK_TBL_LS_INFECTION_HERPES6
6. 2532. {C}~ gbak:    writing data for table TBL_LS_INFECTION_HERPES6

It will take a very long time if I press F8 2530 times.

Can I stop debugging under a certain condition, e.g. when the iteration counter reaches the number 2528?

It's not beautiful, but it might be helpful sometimes:

Code: Pascal  [Select][+][-]

1.           //get position #10 in the line
2.           LineEndingPos_10:= Pos(#10,Buffer);
3.           Counter := 0;
4.           repeat {until LineEndingPos_10 = 0;}
5.             Counter := Counter + 1;
6.             case LineEndingPos_10 of
7.               0:
8.                 begin
9.                   {I need to stop the debugger here...}
10.                   if (Counter = 2530) then
11.                     ShowMessage('Counter is now 2530 or any number you want.');
12.                   BufferStg:= BufferStg + Buffer;
13.                 end;

[Martin_fr]

Breakpoints do have conditions.

If you right click a breakpoint you can go to "breakpoint properties". Or you can do so via the "breakpoint window" from menu view>debugger-win.

https://wiki.lazarus.freepascal.org/IDE_Window:Breakpoints#Breakpoint_properties

If you set condition to:
  i=2000
It will only stop if that evals to true.

The only issue: gdb does not understand strings. So
  s='abc'
will NOT work.
I personally had some success with the following (but others said it did not work for them). Note the double quotes:
   $_streq(^char(s), "abc")
https://sourceware.org/gdb/current/onlinedocs/gdb/Convenience-Funs.html#Convenience-Funs


Alternatively you can use the hitcount property.

[zoltanleo]

@valdir.marcos
@Martin_fr

Thanks so much for the valuable advice.