mktime in include/linux

mktime in include/linux

[Rick Hohensee]

Why does Linux have a mktime routine fully coded in linux/time.h that
conflicts directly with the ANSI C standard library routine of the same
name? It breaks a couple things against libc5, including gcc 3.0. OK, you
don't care about libc5. It's still pretty weird. Wierd? Weird.

Rick Hohensee
www.cLIeNUX.com

:;d -d */
Cintpos/     boot/        device/      incoming/    owner/       temp/
Debian/      command/     floppy/      log/         source/
Linux/       configure/   guest/       lost+found/  subroutine/
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Re: mktime in include/linux

[Erik Mouw]

On Thu, Jun 21, 2001 at 10:30:40PM -0400, Rick Hohensee wrote:
> Why does Linux have a mktime routine fully coded in linux/time.h that
> conflicts directly with the ANSI C standard library routine of the same
> name? It breaks a couple things against libc5, including gcc 3.0. OK, you
> don't care about libc5. It's still pretty weird. Wierd? Weird.

This has been brought up many times on this list: you are not supposed
to include kernel headers in userland.


Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/

Re: mktime in include/linux

[Jonathan Lundell]

At 1:43 PM +0200 2001-06-22, Erik Mouw wrote:
>On Thu, Jun 21, 2001 at 10:30:40PM -0400, Rick Hohensee wrote:
>>  Why does Linux have a mktime routine fully coded in linux/time.h that
>>  conflicts directly with the ANSI C standard library routine of the same
>>  name? It breaks a couple things against libc5, including gcc 3.0. OK, you
>>  don't care about libc5. It's still pretty weird. Wierd? Weird.
>
>This has been brought up many times on this list: you are not supposed
>to include kernel headers in userland.

That's not the problem, I think. Most of time.h, including the 
definition of mktime, is #ifdef __KERNEL__, so it shouldn't be 
breaking anything in userland even if you do include it. And you 
might, in order to obtain the interface definition of struct 
timespec. What's weird is: why is __KERNEL__ getting #defined in 
Rick's userland?

There can't, of course, be any blanket prohibition against using 
kernel headers in userland. Think about ioctl.h, for example.
-- 
/Jonathan Lundell.

Re: mktime in include/linux

[Rick Hohensee]

> 
> At 1:43 PM +0200 2001-06-22, Erik Mouw wrote:
> >On Thu, Jun 21, 2001 at 10:30:40PM -0400, Rick Hohensee wrote:
> >>  Why does Linux have a mktime routine fully coded in linux/time.h that
> >>  conflicts directly with the ANSI C standard library routine of the same
> >>  name? It breaks a couple things against libc5, including gcc 3.0. OK, you
> >>  don't care about libc5. It's still pretty weird. Wierd? Weird.
> >
> >This has been brought up many times on this list: you are not supposed
> >to include kernel headers in userland.
> 
> That's not the problem, I think. Most of time.h, including the 
> definition of mktime, is #ifdef __KERNEL__, so it shouldn't be 
> breaking anything in userland even if you do include it. And you 
> might, in order to obtain the interface definition of struct 
> timespec. What's weird is: why is __KERNEL__ getting #defined in 
> Rick's userland?
> 
> There can't, of course, be any blanket prohibition against using 
> kernel headers in userland. Think about ioctl.h, for example.

Sounds like a clue. Thanks.

Rick

> -- 
> /Jonathan Lundell.
>