mlock not working, variables getting cleared in function switch.
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M using Multiple function in a single '.m' file.
when i make a function call the previous data of the calling function is getting cleared.
Even if i use mlock then also data is getting cleared from in between function calls.
Is there any other method i can preserve variable and data of my main function.
2 Comments
Geoff Hayes
on 25 Aug 2020
as - how are you storing the previous data? Is this data the output from calling this function before? Can you provide an example that demonstrates this problem?
Answers (1)
Jan
on 25 Aug 2020
Edited: Jan
on 25 Aug 2020
Create this file:
function demo(In)
persistent v
switch lower(In)
case 'lock'
mlock
disp('locked')
case 'unlock'
munlock
disp('unlocked')
case 'set'
v = rand
case 'show'
v
end
end
Now run it:
demo('show') % v is []
demo('set')
clear('demo') % v is cleared
demo('show') % v is []
demo('set') % v is set to a value
demo('show') % v keeps its value
demo('lock')
clear('demo') % v is not cleared
demo('show') % v kept its value
demo('unlock')
clear('demo') % v is cleared
demo('show') % v is [] again
So usually declaring a variable as persistent is sufficient already and you need mlock only, if a brute program calls clear all (which is a bad programming pattern!).
2 Comments
Jan
on 30 Aug 2020
Of course the workspaces are cleared,when a function is left, except if a variable is stored persistently. So just import the "ROM file" (what ever this means) into a variable, which is declared as persistent.
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