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From: HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu (Christoph van Wuellen)
Newsgroups: comp.os.minix
Subject: Re: C68
Message-ID: <47503@nigel.ee.udel.edu>
Date: 13 Mar 91 19:04:52 GMT
Sender: mmdf@ee.udel.edu
Lines: 34

As long as no floating point stuff is included, c68 and ACK code can be
mixed. This might not be true for nested structures:

In c68,
struct a {
   struct b {
     char x1;
     char x2;
     char x3;
   };
   char x4;
}

struct a has a length of 6 bytes, with the following offsets:

b.x1 0, b.x2 1, b.x3 2, x4 4

The reason is that the length of every structure is rounded up to the
default alignment. I do not know how ACK treats this, but you have to be
careful when implementing TeX with the web2c package in 32-bit mode:

struct halfword {
   struct v {
     char b0;
     char b1;
   };
   short h0;
}

WIth a default alignment of 32 bit, this structure is 8 bytes long!
because the Sun386 compiler makes this struct 4 bytes long (as it is intended),

I once had problems mixing Sun and c386 code on that application.
C.v.W.