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Setting the value of a CDF parameter

BS202501273649

I am using SKILL to update the properties on an instance.

I am probably missing something obvious but I don't completely understand the difference between the properties as accessed directly on the instance and the CDF parameters defining those same properties.  In particular, for one PDK at least, I am seeing a difference when I set the value via the property versus setting it via the CDF parameter.

In other words between

dbReplaceProp(instance prop_name type(newPropValue) newPropValue)

and

CDF = cdfGetInstCDF(instanceDB)
param = cdfFindParamByName(CDF prop_name)
param~>value = newPropValue

In both cases the property seems to being set "correctly": it appears correctly in the dialog in Virtuoso.  But I am seeing some subtle differences in what is saved in OA.  In particular, this is a boolean and I am trying to make it False by setting it to nil.   In the second case that is indeed what happens but in the first case the property contains an AppPropertyValue containing the bytes "nil" which seems like it might be wrong.

So I'm guessing the second form of the code is what I want but I'm not really sure why.

Parents
  • Andrew Beckett

    In this case it's not callback related as Aurel suggested (although that can be a problem in general). It's that using dbRepaceProp in the manner you have (using the type of the SKILL value to determine the property type) will not work correctly (probably) if you have a value of nil. In SKILL, nil is actually an empty list and is used to represent false - there is no boolean type in SKILL - anything other than nil is true. So type(nil) is list. You'd be creating a list property with an empty list (which is a custom AppProp in OA), rather than a "boolean" property type with value nil (false). If you passed "boolean" as the third arg to dbReplaceProp it would store it a a boolean property, not a list.

    With the CDF-based approach, it knows the type of the CDF parameter, and hence will set the appropriate type of the instance property used to store it.

    Andrew

  • BS202501273649
    in reply to Andrew Beckett

    Ah of course!   The type is wrong - I need to use the CDF parameter type not the type of the data being set when it is nil.  Thanks!  Setting it via the CDF parameter is actually fine and what I am doing but I just needed to understand better.

Reply
  • BS202501273649
    in reply to Andrew Beckett

    Ah of course!   The type is wrong - I need to use the CDF parameter type not the type of the data being set when it is nil.  Thanks!  Setting it via the CDF parameter is actually fine and what I am doing but I just needed to understand better.

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