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From: henry@zoo.toronto.edu
Newsgroups: comp.compilers
Subject: Re: Layout of Structs
Message-ID: <4002@ima.ima.isc.com>
Date: 31 May 89 09:10:50 GMT
References: <3979@ima.ima.isc.com>
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>It is a Good Thing [tm] that structures are laid out in this way.  As
>a hardware type, I often need to write device drivers.  Being able to 
>impose a structure onto a hardware memory map is a very useful thing, 
>indeed.

Beware, however, that it is still possible for C structures to have
unnamed holes in them more or less wherever the compiler pleases.  C
does *not* give you complete control of storage layout, and never has,
although in many compilers you can do pretty much what you want at the
price of having your code depend on assumptions about the compiler.

Case in point:  on a 68020, are longs 16-bit aligned or 32-bit aligned?
Compilers differ.

                                     Henry Spencer at U of Toronto Zoology
                                 uunet!attcan!utzoo!henry henry@zoo.toronto.edu
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