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Subject: Re: Record initialisation question
Newsgroups: comp.lang.ada
References: <5ff9779d$0$24281$426a74cc@news.free.fr>
From: DrPi <314@drpi.fr>
Date: Sun, 17 Jan 2021 18:08:52 +0100
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Le 09/01/2021 à 10:30, DrPi a écrit :
> Hi,
> 
> I'm working on a µP BSP. The boot sequence of this µP requires byte 
> structures located in FLASH memory.
> For example :
> 
>     type t_Dcd_Header is record
>        Tag     : Unsigned_8  := 16#D2#;
>        Length  : Unsigned_16 := 4;      -- Length in byte of the DCD 
> structure (this header included)
>        Version : Unsigned_8  := 16#41#;
>     end record
>       with Object_Size => 32,
>            Bit_Order => System.Low_Order_First;
> 
>     for t_Dcd_Header use record
>        Tag     at 0 range  0 .. 7;
>        Length  at 0 range  8 .. 23;
>        Version at 0 range 24 .. 31;
>     end record;
> 
> The t_Dcd_Header is part of t_Dcd record.
> The Length field of t_Dcd_Header must contain the length of t_Dcd.
> 
>     Dcd : constant t_Dcd :=
>      ( Dcd_Header => ( Length => ???, -- Length of Dcd
>                        others => <>),
>        ...
>      );
> 
> Is there a way to automatically set Length ?
> Dcd goes in a dedicated .txt section.
> 
> Nicolas

I tried to use a C module as a workaround.
I added C to my .gpr file : for Languages use ("Ada", "C");
The C module is compiled correctly. However, it is not linked. This is 
not a surprise since it contains no object used by Ada modules.