On Fri, 22 Mar 2002, Yuchen Zhang wrote: > Hello, > > I have a question about empty optional field. > > It seems that there is no way to indicate one possibility in the OSS C > encodings. That case occurs when a SEQUENCE has an OPTIONAL field, and the > type of that OPTIONAL field is a SEQUENCE OF. It does not seem possible to > distinguish between: > > 1) The field is present but the SEQUENCE OF is empty. > 2) The field is not present. > > The problem comes from: > > A) An empty SEQUENCE OF is represented as a NULL pointer. > B) The absence of an OPTIONAL field of type SEQUENCE OF is indicated by > a NULL pointer. > > It would appear, then, that there is no semantic difference between an > empty SEQUENCE OF and an OPTIONAL field of type SEQUENCE OF that is > not present. Is this true?
No, not true. I'll send you private email in a minute answering your question, as [EMAIL PROTECTED] is meant for general ASN.1 or encoding rules questions, not vendor-specific tech support questions. In the future please send OSS support questions to [EMAIL PROTECTED] or phone +1-732-302-9669 x-1 to speak with a tech support person. Tech support is available 24 hours a day, 7 days a week, so feel free to call whenever you wish. ------------------------------------------------------------------------- Bancroft Scott Toll Free :1-888-OSS-ASN1 OSS Nokalva International:1-732-302-0750 [EMAIL PROTECTED] Tech Support :1-732-302-9669 x-1 1-732-302-9669 x-200 Fax :1-732-302-0023 http://www.oss.com
