[Toybox] [PATCH] include sys/sysmacros.h

[Rich Felker]

On Mon, Feb 29, 2016 at 05:53:02PM -0500, Mike Frysinger wrote:
> On 29 Feb 2016 16:24, Rob Landley wrote:
> > On 02/29/2016 12:36 PM, Mike Frysinger wrote:
> > > The major/minor macros are defined in sys/sysmacros.h.  This has
> > > historically been pulled in implicitly by sys/types.h,
> > 
> > http://man7.org/linux/man-pages/man3/major.3.html says sys/types.h, yes.
> 
> this is merely documenting what glibc has historically done, and glibc
> has historically tried to copy BSD in this area.  even then, the manpage
> probably should be adjusted to document sysmacros.h directly since that
> is where glibc has always placed things.

Defining macros named "major" and "minor" from a standard header is
serious namespace pollution.

Since sys/types.h is a rather quirky historical header that nobody
needs to include anyway, it's not such a horrible thing that glibc's
sys/types.h exposes sys/sysmacros.h However, also for historical
reasons, glibc's stdlib.h includes sys/types.h. This means that every
source file which includes stdlib.h gets the namespace pollution, and
that's really bad. That's why they're trying to fix it.

> > > but C libs
> > > are moving away from that as they aren't in POSIX.  Use the header
> > > directly as defined by BSD systems.
> > 
> > This adds a non-posix header to the posix header section of toys.h,
> 
> i really have no idea how toybox code is structured.  feel free to add
> the include to wherever you feel is appropriate.
> 
> > based on the premise that unspecified C libraries plan to break existing
> > programs at some unknown point in the future, for no obvious reason.
> 
> feel free to read the thread:
> 	https://sourceware.org/ml/libc-alpha/2015-11/msg00253.html
> 
> glibc is the process of deprecating, and musl/uClibc would follow suit,
> if not just drop the include altogether.

musl has never had the issue. :-) because we don't implicitly include
sys/sysmacros.h at all. The set of programs that have any use for
these macros is basically ls, mknod, and archivers (tar, cpio, etc.)
that support archiving device nodes, and these programs can just
include the appropriate header to get them.

Rich

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