How to return UNDEFINED

[jrdp]

[jasper]

The definition you see is for passing as input argument. As output argument - I suppose the easiest it so call .clear() on the passed output argument itself - UNDEFINED for a string value equals an empty string.

[jasper]

What is the context in which you are returning UNDEFINED? Which function is it?

[jrdp]

This question arose whilst working on implementing the GetPresentPhases function of the ICapeThermoMaterial interface. The overall context is implementing a Modelica-CAPE-OPEN interface for Dymola.

[jrdp]

Regarding this particular function, GetPresentPhases, its parameters are CapeArrayString and CapeArrayEnumeration<CAPEOPEN_1_2::CapePhaseStatus>, so there is no clear()-function available. Would a resize(0) on the output parameters comply with the specification of the function?

[jasper]

Yes - UNDEFINED for arrays is an empty array. Indeed resize(0) will do the trick.