Re: [icu-design] ICU4C API proposal: add ucal_setGregorianChange()

[George R. <gr...@us...>]

> Question: Which error code should I set if the calendar is not a
> Gregorian calendar? Reasonable choices from utypes.h seem:
> 
> U_RESOURCE_TYPE_MISMATCH (my favorite for this)
> U_UNSUPPORTED_ERROR
> U_ILLEGAL_ARGUMENT_ERROR

I have a preference for U_UNSUPPORTED_ERROR. U_RESOURCE_TYPE_MISMATCH 
seems to be more of a resource bundle error code.