OpenEuphoria

RE: c structs

• Posted by Chris Bensler <bensler at mail.com> Mar 29, 2002
• 354 views

Thanks Derek,
   Now I understand that much.

What about arrays? and fixed length strings?

EG.
   recName1(1) As Byte
   recName2 As String * 14


Chris


Derek Parnell wrote:
> Try this:
> 
> 
> include tk_mem.e
> 
> -- Type POINT
>     ptX                 = allot( Long ),
>     ptY                 = allot( Long ),
>     SIZEOF_POINT       = allotted_size(),
> 
> -- Type MSG
>     msgHWnd             = allot( Long ),
>     msgMessage          = allot( UInt ),
>     msgWParam           = allot( Long ),
>     msgLParam           = allot( Long ),
>     msgTime             = allot( DWord ),
>     msgPtX              = allot( Long ),
>     msgPtY              = allot( Long ),
>     SIZEOF_MSG          = allotted_size()
> 
> 
> You can then do something like:
> 
>     atom hPoint
> 
>     hPoint = acquire_mem(0, SIZEOF_POINT)
>     store(hPoint, ptX, xvalue)
>     store(hPoint, ptY, yvalue)
> 
> and
> 
>     xvalue = fetch(hPoint, ptX)
>     yvalue = fetch(hPoint, ptY)
> 
> 
> Unless you want to use the low-level access methods:
> 
> 
> -- Type POINT
> contant
>     ptX                = 0,
>     ptY                = 4,
>     SIZEOF_POINT       = 8,
> 
> -- Type MSG
>     msgHWnd             = 0,
>     msgMessage          = 4,
>     msgWParam           = 8,
>     msgLParam           = 12,
>     msgTime             = 16,
>     msgPtX              = 20,
>     msgPtY              = 24,
>     SIZEOF_MSG          = 28
> 
> 
> You can then do something like:
> 
>     atom hPoint
> 
>     hPoint = allocate(SIZEOF_POINT)
>     poke4(hPoint + ptX, xvalue)
>     poke4(hPoint + ptY, yvalue)
> 
> and
> 
>     xvalue = peek4s(hPoint+ptX)
>     yvalue = peek4s(hPoint+ptY)
> 
> -----------
> Derek.
> 
> ----- Original Message ----- 
> From: "Chris Bensler" <bensler at mail.com>
> To: "EUforum" <EUforum at topica.com>
> Sent: Friday, March 29, 2002 11:28 PM
> Subject: c structs
> 
> 
> > I'm trying to convert some structures to eu, and I'm not sure of how 
> > some things are stored.
> > 
> > for example, here are some VB type declares:
> > 
> > Type POINTAPI
> >         x As Long
> >         y As Long
> > End Type
> > 
> > Type MSG
> >     hwnd As Long
> >     message As Long
> >     wParam As Long
> >     lParam As Long
> >     time As Long
> >     pt As POINTAPI
> > End Type
> > 
> > what would the struct size and offsets be? does a struct use any bytes 
<snip>