[lwip-users] [lwip] Packed structures

[Florian Schulze]

Hi!

I'm currently using lwIP in DOS using DJGPP with GCC. I have to
use -fpack-struct for the full library to make it work, but this slows down the
library unnecessarily.
I know the following ways to pack structures in various compilers:
1. GCC
struct foo {
    char a __attribute__((packed));
    int b __attribute__((packed));
}
2. MS Visual C++ 5.0(and up) / GPP (GCC with C++)
#pragma pack(push,1)
struct foo {
    char a;
    int b;
}
#pragma pack(pop)
3. Others I have seen
#pragma pack(1)
struct foo {
    char a;
    int b;
}
#pragma pack()

and

#pragma pack 1
struct foo {
    char a;
    int b;
}
#pragma pack

Does anyone know more? How could this be generalised so only the structs which
really need it are packed like ip_hdr and arp_hdr?
Or should I just fix it for my own use?
Which structs need to be packed? I think there aren't many, only the headers of
the packets.

Florian
--
Florian 'Proff' Schulze - address@hidden
Homepage:               - http://proff.fly.to
PGP-Key available from  - http://www.keyserver.net/en/


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