Messages in this thread | | | Date | Sat, 27 Dec 2008 12:45:25 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86 byteorder.h: use __asm__/__inline__ for userspace |
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Mike Frysinger wrote: > On Saturday 27 December 2008 14:23:19 H. Peter Anvin wrote: >> Mike Frysinger wrote: >>> {su}{8,16,32,64} doesnt matter too much to me vs {u,}int_t{8,16,32,64}_t. >>> as long as people stop using __{su}{8,16,32,64}. using the latter >>> though does mean headers will more likely be "just usable" w/out needing >>> linux/types.h include. but then people would be forced to include >>> stdint.h or similar before a linux header ... and that sucks. >> That is a total non-starter. This would mean that the C library itself >> cannot use these headers without exporting additional symbols into the >> namespace, *WHICH IT IS NOT ALLOWED TO DO*. > > which is already happening today you mean. grep the kernel headers and you'll > see a ton of [u]intXX_t hits.
Now, keep in mind this is only true for headers exported to userspace. But this is correct - which is the base of this conversation (Sam suggesting that they should be warned about, and I suggested auto-converting them.)
> this logic though means that the kernel should not be defining any structures > that the C library is defining (such as asm-generic/fcntl.h). such structs > should get renamed the same way as __[us]XX types
This is also correct, at least for exported headers. For kernel-internal headers, it doesn't matter. Unfortunately we do have at least several cases of exported interfaces with globally visible names.
There is one other exception of note, which is a header file which can only be included by the userspace *application*, using a nonportable top-level include (either directly <linux/*> or indirectly via <sys/*>). In those cases we can be looser about at least structure names. This is common for ioctl structures.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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