[lxc-devel] [PATCH] Link against pthread when not on bionic.

[Stéphane Graber]

On 02/19/2013 09:19 AM, Serge Hallyn wrote:
> Quoting Natanael Copa (ncopa at alpinelinux.org):
>> On Mon, 18 Feb 2013 21:40:42 +0100
>> Daniel Lezcano <daniel.lezcano at free.fr> wrote:
>>
>>> On 02/18/2013 06:23 PM, Stéphane Graber wrote:
>>>> dpkg spotted that we're not explicitly linking against pthread even though
>>>> we use some of its symbols (sem_*).
>>>
>>> uh ? wait.
>>>
>>> We shouldn't link against the lib pthread.
>>>
>>> I don't think sem_* is a symbol coming from the pthread library.
>>
>> Seems to be with uClibc:
>>
>> ncopa-desktop:~$ nm -D /lib/libpthread.so.0.9.32 | grep sem_
>> 000000000000d168 T __new_sem_destroy
>> 000000000000a914 T __new_sem_getvalue
>> 000000000000a414 T __new_sem_init
>> 000000000000c219 T sem_close
>> 000000000000d168 W sem_destroy
>> 000000000000a914 W sem_getvalue
>> 000000000000a414 W sem_init
>> 000000000000c744 T sem_open
>> 0000000000006db0 T sem_post
>> 0000000000006e00 T sem_timedwait
>> 0000000000006f80 T sem_trywait
>> 00000000000095c8 T sem_unlink
>> 0000000000006fb0 T sem_wait
>>
>> How about let autoconf detect what to link against?
>>
>> @@ -274,6 +274,9 @@ AC_CHECK_HEADERS([sys/signalfd.h pty.h sys/capability.h sys/
>>  # Check for some syscalls functions
>>  AC_CHECK_FUNCS([setns pivot_root sethostname unshare])
>>  
>> +# find library for sem_*
>> +AC_SEARCH_LIBS(sem_open, [pthread rt])
> 
> I like it.  thanks.

Won't that cause lxc to link against pthread on most distros which based
on the previous e-mails is something we want to avoid?

I guess we'd want [rt pthread], though as was discussed earlier, it's
very likely that this will fail as for some reason the tools don't see
that librt contains the sem_* symbols.

>> +
>>  # Check for some functions
>>  AC_CHECK_LIB(util, openpty)
>>  AC_CHECK_FUNCS([openpty hasmntopt setmntent endmntent])
>>
>>
>>
>>
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> 
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-- 
Stéphane Graber



-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com

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