DynamicData: get name of optional members modern C++

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DynamicData: get name of optional members modern C++

we're developing an test interface to test some DDS applications, which parses JSON-Topics to IDL-Topics. To achief this, we wrote a function which iterates recursive over the members of a dds::core::xtypes::DynamicData-object – representing a IDL topic – and searches the member names in the JSON object to extract and set the values similar to this example: https://community.rti.com/kb/dynamic-data-how-access-multi-level-nesting-elements-using-c11.

Now the problem:
It seems to be impossible to get the member_name of unset optional members. Access by  member_info(uint32_t index) throws dds::core::error "member does not exists".  First we tried to get the member throug the DynamicData.type().native()._data._members[x], aside the official API. But the order of the type code members is different from DynamicData member order.
So basically we're missing the method "member_name()" for optional members, like it exists for the index: member_index (const std::string &name), which btw. also throws "member does not exists" for unset optional members.

Is there any way to get the name of unset optional members by index?

Best regards

Christian

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This incorrect behavior of member_info was fixed in 6.1.0.

If you can't upgrade, try using the information in the dynamic type (DynamicData::type())

Marc.Chiesa's picture
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You can also try falling back to the C API as a workaround in versions prior to 6.1.0. See this example from the Python API implementation.

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Thank you very much for your both replies!

I could solve the problem by using Marcs solution:

You can also try falling back to the C API as a workaround in versions prior to 6.1.0. See this example from the Python API implementation.

implemented this, to get the member info:

rti::core::xtypes::DynamicDataMemberInfo CJsonParser::get_member_info( const dds::core::xtypes::DynamicData& dd, uint32_t index)
{
   rti::core::xtypes::DynamicDataMemberInfo mi;
   if (!dd.member_exists_in_type(index))
   {
      throw dds::core::InvalidArgumentError("member id " + std::to_string(index) + " does not exist in type");
   }  

   auto rc = DDS_DynamicData_get_member_info(
      &dd.native(),
      &mi.native(),
      nullptr,
      index);
   rti::core::check_return_code(rc, "DynamicData member info error (index)");
   return mi;
}