DDS-XTypes 1.2 RTF Avatar
  1. OMG Issue

DDSXTY12 — Optional flag in TypeObject union members

  • Key: DDSXTY12-11
  • Legacy Issue Number: 19271
  • Status: closed  
  • Source: Real-Time Innovations ( Sumant Tambe)
  • Summary:

    By definition, union members are always optional. The spec should allow implementations to decide whether union members include the optional flag as part of the TypeObject member flags. In any case, implementations should ignore that flag for equality and type-compatibility purposes.

  • Reported: DDS-XTypes 1.1 — Wed, 26 Feb 2014 05:00 GMT
  • Disposition: Resolved — DDS-XTypes 1.2
  • Disposition Summary:

    Indicate the TypeObject union sets the member's isOptional flag to false.

    Union members shall have the IS_OPTIONAL set to 0 since the semantic is that if a member is selected then it has to be present.

    In the future we may want to support the @optional annotation on the union member to indicate that the selected member could be omitted. This is currently not supported in the IDL syntax. However if this were to change in the future, the future version of XTYPES could support it by setting the IS_OPTIONAL flag to 1 for those members.

    Furthermore indicate only the discriminator member can be declared as a key member for the union.

  • Updated: Thu, 22 Jun 2017 16:42 GMT