Re: How to convert record?

[byhoe@greenlime.com (Adrian Hoe)]

"Beard, Frank" <beardf@spawar.navy.mil> wrote in message news:<mailman.1004379548.31870.comp.lang.ada@ada.eu.org>...
> One other thing you might want to consider:
> 
> 
> procedure Write_ABCD (the_Command : Command) is
> 
>    Length : Posix.IO_Count :=
> Posix.IO_Count(the_Command'size/Posix.Posix_Character'size);
>    Buffer : IO_Buffer (1 .. positive(length));
>    for Buffer use at the_Command'address;
> 
> begin
> 
>    POSIX.IO.write (File_Descriptor, Buffer, Length);
> 
> end Write_ABCD;
> 
> 
> I've used it on both Windows and a couple of Unix flavors without
> any problems, but we were always communicating between homogenous 
> platforms (same hardware, same OS).  If you are in a heterogeneous
> environment, you have to use a different method, but you have the
> same problem with Unchecked_Conversion.
> 
> I like it because it's fairly straight forward and it doesn't copy
> data like Unchecked_Conversion, which is particularly good when
> dealing with large buffers.
> 
> Frank


Then you would have to take care of the_Command'Size. The 8-byte
record will give you no problem at all. See my post thread "Size and
Pack".



> 
> -----Original Message-----
> From: joseph_kwan@greenlime.com [mailto:joseph_kwan@greenlime.com]
> 
> 
> Hello,
> 
> I just started to learn Ada and have been playing/working with Ada for
> two weeks now.
> 
> I want to send a command buffer to serial port using florist's POSIX
> interface but I have encountered problems in converting record to
> POSIX.IO.IO_Buffer or Ada.Streams.Stream_Element_Array. How can I
> overcome this problem?
> 
> package ABCD is
> 
>    type Command is
>       record
>           A : Character;
>           B : Character;
>           C : Integer;
>           D : Long_Integer;
>       end record;    -- total 8 bytes;
> 
> ...
> end ABCD;
> 
> 
> POSIX.IO.write (File_Descriptor, Command, Length);
> 
> where 
> 
>    procedure Write
>      (File           : in File_Descriptor;
>       Buffer         : in IO_Buffer;
>       Last           : out POSIX.IO_Count;
>       Masked_Signals : in POSIX.Signal_Masking
>                      := POSIX.RTS_Signals);
> 
> I have searched the CLA but do not find any solutions. Can you please
> help?
> 
> Thank you.
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