Re: Importing C structs?

[chris <spamoff.danx@ntlworld.com>]

Freejack wrote:
> I'm finally starting to get an idea(at least I think I am.) on handling
> interfacing to C.

Really?  I don't think I'll ever get the hang of it.

> Specifically, would I cast DBTYPE as a seperate record type, and then
> provide a seperate function to translate each item into the type expected
> by the C struct? Or can import the DBTYPE struct whole hog into my Ada
> specification?

Make an Ada record corresponding to that type.  Map it's fields to 
things from interfaces.c and other records.  Then use

pragma Convention(C, DBType);

I think!

This is from my ongoing work on a libjpeg binding...

    type Jpeg_Error_Mgr is record
       Error_Exit          : Error_Exit_Handler;
       Emit_Message        : Emit_Message_Handler;
       Output_Message      : Output_Message_Handler;
       Format_Message      : Format_Message_Handler;
       Reset_Error_Mgr     : Reset_Error_Handler;
       Msg_Code            : C.Int;
       Msg_Parm            : System.Address;
       Trace_Level         : C.Int;
       Num_Warnings        : C.Long;
       Jpeg_Message_Table  : Jpeg_Message_TableT;
       Last_Jpeg_Message   : C.Int;
       Addon_Message_Table : Jpeg_Message_TableT;
       First_Addon_Message : C.Int;
       Last_Addon_Message  : C.Int;
    end record;

    pragma Convention (C, Jpeg_Error_Mgr);


HTH,
Chris