On 26 Feb 2012, at 13:54, ik wrote:
> to the following Pascal record:
>
>
> iphdr = record
> {$IFDEF ENDIAN_LITTLE}
> jhl : Cardinal; // __u8 ihl:4,
> version : Cardinal; // version:4
The ":4" in C means "4 bits", not 4 bytes. The correct translation in the
general case for bitfields is hard, because FPC does not support C-compatible
bitpacking (it depends on the type of the bitfield, e.g. "int a:4;" and "char
a:4" have different alignment rules). In this case, this should match the C
layout:
{$packrecords c}
iphdr = record
bitfields = bitpacked record
{$IFDEF ENDIAN_LITTLE}
jhl: 0..(1 shl 4)-1;
version: 0..(1 shl 4)-1;
{$ELSE}
jhl: 0..(1 shl 4)-1;
version: 0..(1 shl 4)-1;
{$ENDIF}
end;
tos : cuint8;
tot_len : cint16;
id : cint16;
frag_off : cint16;
ttl : cint8;
protocol : cint8;
check : cuint16;
saddr : cint32;
daddr : cint32;
end;
You will then of course have to use iphdrvar.bitfields.jhl instead of
iphdrvar.jhl.
Jonas_______________________________________________
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