[U-Boot] [PATCH] flash.h: pull in common.h for types

Wolfgang Denk
2009-11-17T21:56:58Z

Dear Scott Wood,

In message <4B031158.20501@freescale.com> you wrote:
>
> > My question: is there a definitive position somewhere (for example
> > for the Linux kernel; I'm sure we don't have one for U-Boot [yet]),
> > whether system headers should be self-sufficient?
>
> I'd say they should be self-sufficient, in that the inclusion of the
> header itself should not fail if I haven't included some arbitrary other
> header. I don't see what the argument would be for not doing this.

Well, Theo de Raadt says for example "... people would be able to
include less files; indeed, almost be careless about what they
include. But this would not increase portability in any way. And
'make build' would probably, if it was taken the nth degree, take
twice as long. Therefore there is no benefit for the crazy rule you
suggest..." - see
http://www.mail-archive.com/tech at openbsd.org/msg00425.html

> I don't know whether Linux has a specific policy on this, but I haven't
> noticed many problems in this regard, and when I did find one in the
> kernel a few years back I didn't get any argument when I submitted a
> patch to fix it.
>
> Which man pages are you looking at?

Well, for example:

open(2):
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

mknod(2):
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

stat(2):
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

Why do we need these lists of #includes? WHy doe - for example -
<sys/stat.h> not auto-include anything it might need?

To me this seems to be an indication that there is no intention to
make headers self-sufficent, but I am absolutely not sure.

Best regards,

Wolfgang Denk

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