how to set and get value of optional members?

4 posts / 0 new
Log in or register to post comments
Last post
Tue, 07/18/2023 - 01:59
#1
RareLonely
Offline
Last seen: 4 days 1 hour ago
Joined: 01/13/2016
Posts: 58
how to set and get value of optional members?

Hi, everyone

I have a idl defined like this:

struct StdEntity

{

    boolean valid; //@Optional

    char id[20];

    long type[100]; //@Optional

    double val[1500]; 

};

the member valid and val does not transfer every time, so i want known that how to set and get value for these optional members.

thanks for any help

Keywords:
Top
Tue, 07/18/2023 - 02:01
RareLonely
Offline
Last seen: 4 days 1 hour ago
Joined: 01/13/2016
Posts: 58

My program is developed using C++ language， and dds version 5.2.3.

Top
Tue, 07/18/2023 - 03:38
Howard
Howard's picture
Offline
Last seen: 1 day 16 hours ago
Joined: 11/29/2012
Posts: 605

Are you using Modern C++ (aka C++03/C++11) or the Traditional C++ API (aka C++98)?

If using the Traditional C++ API, the IDL definition fundamentally maps into a class with publically accessible members of the type described in the IDL.  @optional members are mapped to pointers of the same type

e.g.

long type[100]; //@optional

is mapped to

long *type[100];

 

set the pointer to NULL to not send data for the array.  When received, you test to see if the pointer is NULL, if so, then it wasn't sent.  You can just check the header file that defines the data type for this.

 

If using Modern C++, then the type gets encasulated into a dds::optional object.  See the documentation here:

https://community.rti.com/static/documentation/connext-dds/5.2.3/doc/api/connext_dds/api_cpp2/classdds_1_1core_1_1optional.html

 

 

 

Top
Tue, 07/18/2023 - 07:18
RareLonely
Offline
Last seen: 4 days 1 hour ago
Joined: 01/13/2016
Posts: 58

thanks, i got it，its turely a pointer.

Top