Re: [OE-core] [RFC PATCH 2/3] kbd: Disable 64 bit time with 32 bit glibc

[Ola x Nilsson <ola.x.nilsson@axis.com>]

And here is a link to the documentation for the _TIME_BITS Feature Test
Macro
https://www.gnu.org/software/libc/manual/html_node/Feature-Test-Macros.html#index-_005fTIME_005fBITS

The docs for _FILE_OFFSET_BITS is just above.

/Ola

On Tue, Nov 08 2022, Ola x Nilsson wrote:

> Sorry, that link did not explain the -D_USE_TIME_BITS=64 flag.
>
> I was sure I had read official docs of this somewhere but now I can only
> find https://sourceware.org/glibc/wiki/Y2038ProofnessDesign#Detailed_implementation
>
> /Ola
>
> On Tue, Nov 08 2022, Ola x Nilsson wrote:
>
>> As far as I can tell from glibc's documentation, this is how you are
>> supposed to do it.  glibc chose to always support both 32 and 64 bit
>> APIs for time and file offset and make the normal int size the default.
>> musl chose to switch to 64bit altogether. 
>>
>> https://www.gnu.org/software/libc/manual/html_node/64_002dbit-time-symbol-handling.html
>>
>> /Ola
>>
>> On Tue, Nov 08 2022, Alexander Kanavin wrote:
>>
>>> I suppose what I want to say is - perhaps this should be discussed
>>> with upstreams first? Things should 'just work' without having to set
>>> some magic flags in an external configuration.
>>>
>>> Alex
>>>
>>> On Tue, 8 Nov 2022 at 13:18, Alexander Kanavin via
>>> lists.openembedded.org <alex.kanavin=gmail.com@lists.openembedded.org>
>>> wrote:
>>>>
>>>> Is this a recommendation somewhere official?
>>>>
>>>> Alex
>>>>
>>>> On Tue 8. Nov 2022 at 13.04, Niko Mauno <niko.mauno@vaisala.com> wrote:
>>>>>
>>>>> My understanding wrt. Y2038 and 32-bit glibc hosts was such that it
>>>>> makes sense to set said compiler flags globally to ensure user space
>>>>> wide Y2038 compliance. So I encountered this compiler error while
>>>>> building poky reference images with additional effective
>>>>>
>>>>>    TARGET_CPPFLAGS += "-D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64"
>>>>>
>>>>> declaration in meta/conf/distro/include/tclibc-glibc.inc.
>>>>>
>>>>> -Niko
>>>>>
>>>>> On 8.11.2022 13.50, Alexander Kanavin wrote:
>>>>> > So you need to set -D_TIME_BITS=64
>>>>> > -D_FILE_OFFSET_BITS=64 to get some error? But why set that, shouldn’t
>>>>> > the defaults work?
>>>>> >
>>>>> > Alex
>>>>> >
>>>>> > On Tue 8. Nov 2022 at 12.48, Niko Mauno <niko.mauno@vaisala.com
>>>>> > <mailto:niko.mauno@vaisala.com>> wrote:
>>>>> >
>>>>> >     I have not studied the issue, but in order to reproduce this error I
>>>>> >     add
>>>>> >     'MACHINE = "qemuarm"' to local.conf then issue 'bitbake kbd' against
>>>>> >     current master while TARGET_CPPFLAGS value is set to "-D_TIME_BITS=64
>>>>> >     -D_FILE_OFFSET_BITS=64".
>>>>> >
>>>>> >     -Niko
>>>>> >
>>>>> >     On 8.11.2022 11.14, Alexander Kanavin wrote:
>>>>> >      > We do build for 32 bit arm targets, so is this seen only in specific
>>>>> >      > circumstances? What are they?
>>>>> >      >
>>>>> >      > Alex
>>>>> >      >
>>>>> >      > On Tue, 8 Nov 2022 at 01:09, Niko Mauno via
>>>>> >     lists.openembedded.org
>>>>> >     <http://lists.openembedded.org/
>>>>> >      > <niko.mauno=vaisala.com@lists.openembedded.org
>>>>> >     <mailto:vaisala.com@lists.openembedded.org>> wrote:
>>>>> >      >>
>>>>> >      >> For now add exemption in order to avoid following failure during
>>>>> >      >> do_compile()
>>>>> >      >>
>>>>> >      >>    |
>>>>> >     .../build/tmp/work/cortexa15t2hf-neon-poky-linux-gnueabi/kbd/2.5.1-r0/recipe-sysroot-native/usr/bin/arm-poky-linux-gnueabi/../../libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/12.2.0/ld:.libs/libtswrap.ver:2:
>>>>> > syntax error in VERSION script
>>>>> >      >>    | collect2: error: ld returned 1 exit status
>>>>> >      >>
>>>>> >      >> Signed-off-by: Niko Mauno <niko.mauno@vaisala.com
>>>>> >     <mailto:niko.mauno@vaisala.com>>
>>>>> >      >> ---
>>>>> >      >>   meta/recipes-core/kbd/kbd_2.5.1.bb
>>>>> >     <http://kbd_2.5.1.bb/
>>>>> >      >>   1 file changed, 3 insertions(+)
>>>>> >      >>
>>>>> >      >> diff --git a/meta/recipes-core/kbd/kbd_2.5.1.bb
>>>>> >     <http://kbd_2.5.1.bb/
>>>>> >      >> index aa3ab6e121..b623aecd36 100644
>>>>> >      >> --- a/meta/recipes-core/kbd/kbd_2.5.1.bb
>>>>> >     <http://kbd_2.5.1.bb/
>>>>> >      >> +++ b/meta/recipes-core/kbd/kbd_2.5.1.bb
>>>>> >     <http://kbd_2.5.1.bb/
>>>>> >      >> @@ -18,6 +18,9 @@ SRC_URI =
>>>>> >     "${KERNELORG_MIRROR}/linux/utils/${BPN}/${BP}.tar.xz \
>>>>> >      >>
>>>>> >      >>   SRC_URI[sha256sum] =
>>>>> >     "ccdf452387a6380973d2927363e9cbb939fa2068915a6f937ff9d24522024683"
>>>>> >      >>
>>>>> >      >> +# Compiling 64 bit time for 32 bit host is broken
>>>>> >      >> +GLIBC_64BIT_TIME_CPPFLAGS = ""
>>>>> >      >> +
>>>>> >      >>   PACKAGECONFIG ?= "${@bb.utils.filter('DISTRO_FEATURES', 'pam',
>>>>> >     d)} \
>>>>> >      >>                     "
>>>>> >      >>
>>>>> >      >> --
>>>>> >      >> 2.36.1
>>>>> >      >>
>>>>> >      >>
>>>>> >      >>
>>>>> >      >>
>>>>> >
>>>>
>>>>
>>>> 
>>>>
>>> [4. ATT00001.txt --- text/plain; ATT00001.txt]...
>
> [4. ATT00001.txt --- text/plain; ATT00001.txt]...