[news.eclipse.dsdp.rtsc] Re: Issue with declaring structure variable and

[dave russo <d-russo@xxxxxx>]

If I understand what you're looking for, I don't believe it's possible.

It sounds like you want specify the size of a module instance's creation 
parameters at configuration time.  For example

Mod.xdc:
    module Mod {
        config Int ARR_SIZE = 2;
    instance:
        config Int myArr[ARR_SIZE] = [0, 0];
    }

User's .cfg script:
    var Mod = xdc.useModule("...Mod");
    Mod.ARR_SIZE = 10;

User's .c code:
    main() {
        Mod_Params params;
        Mod_Handle inst;

        Mod_Params_init(&params);
        for (i = 0; i < Mod_ARR_SIZE; i++) {
            params.myArr[i] = i;  /* ERROR: myArr has just 2 elements */
        }
        inst = Mod_create(&params, NULL);
    }

But the .c file is, in general, compiled before the configuration script 
is run.  As a result, the space allocated by the compiler on the stack 
for params (i.e., sizeof(Mod_Params)), can't change as the result of 
configuration.

An alternative might be to "allocate" the array in the instance object 
itself and allow the user to initialize this array via an instance 
method, say Mod_initArray().  The params structure can be initialized to 
a default array whose size and values are controlled by config 
parameters.  This makes the instance usable even if the user does not 
call Mod_initArray().

User's .c code:
    Int myArr[10] = [1, ...];

    main() {
        Mod_Params params;
        Mod_Handle inst;

        Mod_Params_init(&params);
        inst = Mod_create(&params, NULL);
        Mod_initArray(inst, myArr, sizeof(arr));
    }

Ravindranath wrote:
> dave,
>
> For example   i have the following  configuration in  xdc file
>
> config  UInt32 ARR_SIZE = 2;
>
> instance:
>
> config UInt32 myArr[ARR_SIZE ]= [0,0] /* here normal procedure is to 
> initialize all the 2 elements. Suppose if ARR_SIZE is changed  to a 
> higher value through the cfg file static initialization of myArr gives 
> error. To avoid this static initialization of myArr needs  to be done 
> some how  either in xs file  or some other place.
>
> why we  need this type of declaration is application users  does not 
> like to have pointers to which they have to declare variables and  
> assign them to pointers in Params.
>
> Regards,
> Ravindranath Andela