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Author Topic: [LAMW] Setlength causes the app to crash  (Read 6087 times)

Josh

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Re: [LAMW] Setlength causes the app to crash
« Reply #15 on: December 21, 2021, 10:39:33 pm »
hi

using l:=l*2; to setlength makes for a massive array
with 28bytes per record at step  29 its nearly 4GB in size

« Last Edit: December 21, 2021, 10:41:07 pm by josh »
Development Installation Lazarus 1.3, FPC 2.7.1,Windows 7/8 32/64, OSX, *nix

Test Environment Lazarus & FPC Trunk on Windows and OSX (Cocoa Mainly on OSX). Testing also Crosscompile windows to OSX.. 
Any posts made from 2015 will be based on Lazarus Trunk.

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #16 on: December 21, 2021, 10:42:13 pm »
Do you use pointers in your code?

Run your app
Clear the log with adb logcat -c
Start the log with errors using: adb logcat *:E
Crash your app
Stop the log using CTRL+C
Paste the result here

Like this post if you can.

For more, check: adb logcat --help

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #17 on: December 21, 2021, 10:45:07 pm »
hi

using l:=l*2; to setlength makes for a massive array
with 28bytes per record at step  29 its nearly 4GB in size

Yes. Since we don't know why his app crashed, I was hoping for a big value in l. The other possibility, corrupt memory. In both cases SetLength is not the problem. His code has a bug somewhere else.
« Last Edit: December 21, 2021, 10:46:57 pm by engkin »

r.lukasiak

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Re: [LAMW] Setlength causes the app to crash
« Reply #18 on: December 21, 2021, 10:52:37 pm »
interestingly, if I change the record fields to
Code: Pascal  [Select][+][-]
  1.     ChatID:  string;
  2.     FromID:  string;
  3.     Msg:     string;
  4.     mtype:   string;
  5.     tstamp:  TDateTime;
  6.     status:  DWORD;
everything is ok. It's exactly like the other variable.

Well, anyway I already did the procedure in a different way, using just array of integer and the rest of data is taken directly from the database but it just makes me wonder what's wrong with that record  :o

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Do you use pointers in your code?
no pointers.

I'm googling for adb logcat but it seems to be for emulators, isn't it? I'm testing on a physical phone

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #19 on: December 21, 2021, 10:55:48 pm »
I'm googling for adb logcat but it seems to be for emulators, isn't it? I'm testing on a physical phone

No. It works for the physical device.

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #20 on: December 21, 2021, 11:00:33 pm »
Your change does not reveal the bug. It is still there. It might show up again in a different way. Save a copy of your project where it crashes with Setlength.

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #21 on: December 21, 2021, 11:10:27 pm »
Just for my curiosity:

What versions of FPC/Lazarus are you using?
Is the cash happening on the first time you call Setlength with this variable?
What optimization level you have for the project?

r.lukasiak

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Re: [LAMW] Setlength causes the app to crash
« Reply #22 on: December 21, 2021, 11:34:19 pm »
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What versions of FPC/Lazarus are you using?
version: 2.0.12 r64642 + LAMW + aarch64 (installed using fpcdeluxe)

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Is the cash happening on the first time you call Setlength with this variable?
yes. It's actually the only SetLength on this variable

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What optimization level you have for the project?
-O3

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Your change does not reveal the bug. It is still there. It might show up again in a different way. Save a copy of your project where it crashes with Setlength.
I've just brought back the record fields and it worked... How the heck? :o


r.lukasiak

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Re: [LAMW] Setlength causes the app to crash
« Reply #23 on: December 21, 2021, 11:44:42 pm »
Now I even changed the naming to the original Message/Messages and it's still working o.O

engkin

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Re: [LAMW] Setlength causes the app to crash
« Reply #24 on: December 22, 2021, 12:35:20 am »
Message/Messages is not a problem as I showed in my test above.

Make a visual change in your code in the same file where you call Setlength to be certain it is compiled and included in your app.

r.lukasiak

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Re: [LAMW] Setlength causes the app to crash
« Reply #25 on: December 22, 2021, 01:18:32 am »
I already added some lines, compiled and tested several times. So far everything seems to be in tact.

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Message/Messages is not a problem as I showed in my test above.
yes, but it was one of ideas so I wanted to check it out, to make sure it's not the culprit.

Thanks everyone for ideas, I'll leave the topic open, in case the problem appears again.

 

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