Re: [lwip-users] Trouble at compile time with __packed attribute.

[address@hidden]

I haven't used your compiler, but from what you say, I think you can 
leave away the PACK_STRUCT_FIELD() define, since lwIP only uses 
completely packed structs, not normal structs with packed members.

Simon


Yann Suisini wrote:
> Hello,
>
> I'm trying to compile lwip using Keil ARM compiler but it returns an error 
> in ip_frag.c  :
>
> lwip\src\core\ipv4\ip_frag.c(91): error:  #1030: struct "struct pbuf"
> previously declared without __packed
>
> at 
>
> PACK_STRUCT_BEGIN
> struct ip_reass_helper {
>   PACK_STRUCT_FIELD(struct pbuf *next_pbuf);    <---------------
>   PACK_STRUCT_FIELD(u16_t start);
>   PACK_STRUCT_FIELD(u16_t end);
> } PACK_STRUCT_STRUCT;
> PACK_STRUCT_END
>
> According to the doc of Keil compiler I have to use the define attribute
> like this :
> __packed struct foo
> {
>     char one;
>     short two;
>     char three;
>     int four;
> } c;
> for a packed struct 
>
>  struct foo
> {
>     char one;
>     __packed short two;
>     char three;
>     int four;
> } c;
> for a packed field
>
> So in cc.h I have this :
> #ifndef PACK_STRUCT_BEGIN
> #define PACK_STRUCT_BEGIN __packed
> #endif /* PACK_STRUCT_BEGIN */
>
> #ifndef PACK_STRUCT_END
> #define PACK_STRUCT_END
> #endif /* PACK_STRUCT_END */
>
> #ifndef PACK_STRUCT_FIELD
> #define PACK_STRUCT_FIELD(x) __packed x
> #endif /* PACK_STRUCT_FIELD */
>
> #ifndef PACK_STRUCT_STRUCT
> #define PACK_STRUCT_STRUCT
> #endif /* PACK_STRUCT_STRUCT */
>
>
> It seems the compiler don't understand the field is a pointer to a struct 
> and not a structure itself .
> I really don't know how to write it without getting an error :-(
>
> Yann.
>
>  
>
>
>