Is FORMAT DEBUG still any useful?

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Bruno Luong
Bruno Luong on 13 Jan 2021
Commented: cr on 2 Aug 2023
Can someone has an explanation for this (R2020B)
clear
clc
x=1;
y=x;
x=x+1;
format debug
y
x
that produces
y =
Structure address = 23ebc936f80
m = 1
n = 1
pr = 23edbdd6660
1
x =
Structure address = 23ebc936f80
m = 1
n = 1
pr = 23edbdd6660
2
So x and y have the same structure address and data address, yet data are different (1 for y and 2 for x).
Finish the time where FORMAT DEBUG returns useful information for us.
  2 Comments
James Quinlan
James Quinlan on 30 Jun 2021
Hi Bruno, were you able to submit a bug report? I am running into similar issues. I am performing memory tests and tests are unreliable in light of your comment. I reproduce results from both you and James Tursa below giving same addresses for x and y even after x has been modified. I am running Version: 9.10.0.1602886 (R2021a).
My test is slightly different in the sense, I assign x a value, then pass it to a function and make assignment, y = x. From my understanding, if you pass x to a function and don't update it while there, it effectively is pass by reference.
Bruno Luong
Bruno Luong on 1 Jul 2021
Edited: Bruno Luong on 1 Jul 2021
Hi James,
I did not submitted a BUG report. IMO TMW has changed complemetly the shared memory paradism and they just are not willing to share the new mechanism.

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Accepted Answer

James Tursa
James Tursa on 13 Jan 2021
Strange behavior and probably deserves a bug report. E.g.,
R2019a:
>> x = 1;
>> y = x;
>> x = x + 1;
>> format debug
>> y
y =
Structure address = fa4a7890
m = 1
n = 1
pr = 119f97b20
1
>> x
x =
Structure address = fa4a76d0
m = 1
n = 1
pr = 17c869780
2
R2019b:
>> x = 1;
>> y = x;
>> x = x + 1;
>> format debug
>> y
y =
Structure address = f7ef7ac0
m = 1
n = 1
pr = 145dbaec0
1
>> x
x =
Structure address = f7ef7ac0
m = 1
n = 1
pr = 145dbaec0
2
R2020a:
>> x = 1;
>> y = x;
>> x = x + 1;
>> format debug
>> y
y =
Structure address = 192d47e2d40
m = 1
n = 1
pr = 192d3b7a5c0
1
>> x
x =
Structure address = 192d47e2d40
m = 1
n = 1
pr = 192d3b7a5c0
2
So the problem goes back as far as R2019b.
  1 Comment
cr
cr on 2 Aug 2023
Is there a closure to this? I still see the same behaviour in 2023a.

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