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Posted to users@qpid.apache.org by Joe Ly <jo...@mikelinc.com> on 2012/10/18 21:33:17 UTC

Try to send a user-defined struct using C++ QPID

Hi,

Anyone knows how I could send a C/C++ user-defined struct that encodes into qpid messages?

For example, my struct is defined as

struct a {
      int j;
      float k;
      float r[29];
} a;


Thanks,


Joe Ly

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RE: Try to send a user-defined struct using C++ QPID

Posted by Joe Ly <jo...@mikelinc.com>.
For the first case,
if I use a Variant::Map, after I received and decoded the message to get my struct, how could I extract Variant::List and Variant::Map correctly?

Example:
//sender
		Message message;

		Variant::Map content;
		content["id"] = 987654321; //int
  	 	content["name"] = "Widget";//string
   		content["percent"] = 0.99; //double

   		Variant::List colours;
   		colours.push_back(Variant("red"));
   		colours.push_back(Variant("green"));
   		colours.push_back(Variant("white"));
   		content["colours"] = colours;

   		Variant::Map dimensions;
   		dimensions["length"] = 10.2;
   		dimensions["width"] = 5.1;
   		dimensions["depth"] = 2.0;
   		content["dimensions"]= dimensions;  		

   		encode(content, message);

   		sender.send(message, true);
		

		//receiver
		Message message_receive = receiver.fetch(Duration::SECOND * 1);
		
		Variant::Map content1;
		decode(message_receive, content1);
		
		//extract contents from received message
		int identification = content1["id"];
		string name1 = content1["name"];
		double percent1 = content1["percent"];

                ???Variant::List colours_received = content["colours"]; ??? (Is this right?)
                ???Variant::Map dimensions_received = content["dimensions"]; ???
                

Thanks,


Joe Ly

________________________________________
From: Andy Goldstein [andy.goldstein@redhat.com]
Sent: Thursday, October 18, 2012 3:38 PM
To: users@qpid.apache.org
Subject: Re: Try to send a user-defined struct using C++ QPID

Hi Joe,

You have a couple of tried & true options.  You could manually copy the data from the struct into a Variant::Map and encode that into a Message.  You could use a library such as Google Protocol Buffers to both store the data in memory (i.e. instead of using a struct you'd use a protobuf generated class) and for transmission across the wire (since it serializes to/from a string).

Hope this helps,
Andy

On Oct 18, 2012, at 3:33 PM, Joe Ly wrote:

> Hi,
>
> Anyone knows how I could send a C/C++ user-defined struct that encodes into qpid messages?
>
> For example, my struct is defined as
>
> struct a {
>      int j;
>      float k;
>      float r[29];
> } a;
>
>
> Thanks,
>
>
> Joe Ly
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@qpid.apache.org
> For additional commands, e-mail: users-help@qpid.apache.org
>


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Re: Try to send a user-defined struct using C++ QPID

Posted by Andy Goldstein <an...@redhat.com>.
Hi Joe,

You have a couple of tried & true options.  You could manually copy the data from the struct into a Variant::Map and encode that into a Message.  You could use a library such as Google Protocol Buffers to both store the data in memory (i.e. instead of using a struct you'd use a protobuf generated class) and for transmission across the wire (since it serializes to/from a string).

Hope this helps,
Andy

On Oct 18, 2012, at 3:33 PM, Joe Ly wrote:

> Hi,
> 
> Anyone knows how I could send a C/C++ user-defined struct that encodes into qpid messages?
> 
> For example, my struct is defined as
> 
> struct a {
>      int j;
>      float k;
>      float r[29];
> } a;
> 
> 
> Thanks,
> 
> 
> Joe Ly
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@qpid.apache.org
> For additional commands, e-mail: users-help@qpid.apache.org
> 


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