Re: Sockets, Streams, and Element_Arrays: Much confusion

[Mark Gardner <magardner2017@gmail.com>]

On 31/12/2022 19:39, Simon Wright wrote:
> [...]
> 
> The approach we adopted was to create a 'memory stream', which is a
> chunk of memory that you can treat as a stream (see for example
> ColdFrame.Memory_Streams at [1]). With Ada2022, you should be able to
> use Ada.Streams.Storage.Bounded[2].
> 

Wait, so if I know what shape my data is, and use a memory_stream (like 
the one in the Big Online Book of Linux Ada Programming chapter 11 [1]), 
I'm fine using Stream, in conjunction with Get_Address? That's 
wonderful. Not at all frustrated that I just wasted approximately three 
working days looking for a solution to a problem that didn't exist.

> Message'Write the record into the memory stream;
> transmit the written contents as one datagram.

I'm guessing with Memory_Stream'Write(Socket_Stream, Buffer);?

> 
> To read, create a memory stream large enough for the message you expect;
> read a datagram into the memory stream;
> Message'Read (Stream => the_memory_stream, Item => a_message);

Does this second buffer need to be added? If the datagram arrives (UDP), 
shouldn't GNAT.Sockets.Stream() be able to handle it?
> 
> You can use gnatbind's switch -xdr to "Use the target-independent XDR
> protocol for stream oriented attributes instead of the default
> implementation which is based on direct binary representations and is
> therefore target-and endianness-dependent".

Oh fun, I didn't think of that aspect. Thanks! Would I have to pass it 
as a command line flag, or would there be some kind of pragma I could use?

Thanks for the help so far, and happy new year!

[1] http://www.pegasoft.ca/resources/boblap/11.html#11.12