Dynamic memory problems

2020-03-22T23:31:39.014000Z

Hi to all,

In my project I need to use a memory dynamic allocation, able to use an oriented object program. I have enabled the right option doing the following steps:

Right click on the application properties
Dynamic memory settings
Enable "Use dynamic memory allocation" and set the maximum size of memory

after that I am able to use the __NEW operator in this way:

VAR
    n_token          :UDINT;
    init        :BOOL :=FALSE;
END_VAR

IF(NOT init) THEN

    token := __NEW(STRING, 4);
    init := TRUE;

END_IF

In this way the code working fine, but doing this I got an exception in runtime mode

VAR
    n_token               :UDINT;
    init             :BOOL :=FALSE;
    length           :UDINT := 4;
END_VAR

IF(NOT init) THEN

    token := __NEW(STRING, length);
    init := TRUE;

END_IF

Now, I would like understand why in this case the code dosn't work giving me an exception error. Am I doing something of wrong?

Thank you
Luca

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