loading multi threaded library into executable enabled for single thread

[Jeremy Chadwick]

On Fri, Sep 12, 2008 at 11:00:18AM -0400, Barry Andrews wrote:
> Thanks for the links! But I'm not sure what any of this has to do with  
> this particular issue. I have an exe that does not use threads that  
> loads a lib that is linked with libpthread. Why does different threading  
> implementations affect what I am seeing here? Is there no way for this  
> to work in FreeBSD v5.5? Why would this go away if I upgraded to 6.x or  
> better?

You're confusing me.  Earlier you said:

>>>>>>> I have a multi-threaded library that is linked against libpthread.
>>>>>>> When I
>>>>>>> load this lib into a tclsh process on FreeBSD, I get this error,

So what is "the exe?"  Are you referring to tclsh?  If so, you need to
rebuild tclsh from source to link with libpthread.  If not, you need to
contact whoever provided the binary and ask them to rebuild it from
source.

Additionally, please ensure that the tclsh binary is linked to the same
version of libpthread library as your own library.  You want to make
sure they're both built and linked on the same machine (from the same
source code) if possible; the simple ".so.X" versioning method works
great for major changes, but there are often minor changes that don't
result in "X" being increased.

I'm getting the impression that the tclsh binary you have was not built
on the same machine / from the same source as what your library (the one
linked with libpthread) was.

> Jeremy Chadwick wrote:
>> On Fri, Sep 12, 2008 at 09:26:37AM -0400, Barry Andrews wrote:
>>   
>>> I don't understand. If it was not broken, then why did it change in later
>>> FreeBSD versions?
>>>     
>>
>> I should be more explicit: the threading library and implementations
>> have changed over time.  There was libc_r, then there was libthr, then
>> there was libkse.  This is what we call "evolution".  :-)
>>
>> http://www.unobvious.com/bsd/freebsd-threads.html
>> http://kerneltrap.org/node/624
>> http://www.freebsd.org/kse/
>>
>> The gcc -pthread flag is still there on present-day FreeBSD (6 through
>> HEAD), and *should* be used.  You can choose not to use it but you must
>> ensure during linktime that you explicitly link to -lpthread.
>>
>>   
>>> On Fri, Sep 12, 2008 at 9:10 AM, Jeremy Chadwick <koitsu at freebsd.org> wrote:
>>>
>>>     
>>>> On Fri, Sep 12, 2008 at 07:41:14AM -0400, Barry Andrews wrote:
>>>>       
>>>>> Do you know if this is documented in Release Notes or Known Issues or
>>>>> somewhere?
>>>>>         
>>>> Why would it be an "issue"?  gcc -pthread and libpthread linking is
>>>> documented pretty much everywhere on the web.  There isn't anything
>>>> broken about it, it's how it's done on older FreeBSD.
>>>>
>>>> Note that all of this has significantly changed in later FreeBSD
>>>> versions, and that the 5.x series was deprecated a very long time ago.
>>>>
>>>>       
>>>>>> On Thu, 11 Sep 2008, Barry Andrews wrote:
>>>>>>
>>>>>>           
>>>>>>> Hi All,
>>>>>>>
>>>>>>> I have a multi-threaded library that is linked against libpthread.
>>>>>>> When I
>>>>>>> load this lib into a tclsh process on FreeBSD, I get this error,
>>>>>>> "Recurse on
>>>>>>> private mutex". and crash. I understand that I can have this issue
>>>>>>> when the
>>>>>>> executable is not linked against libpthread but one of the loaded
>>>>>>> libs is.
>>>>>>> Basically, it thinks it's in single threaded mode.
>>>>>>>             
>>>>>> This must be an older version of FreeBSD.  I think you must
>>>>>> link your application (tclsh or whatever) against libpthread
>>>>>> in order for this to work.  The libc functions won't get properly
>>>>>> overloaded by their equivalents in libpthread unless you do
>>>>>> this.
>>>>>>           
>>>> --
>>>> | Jeremy Chadwick                                jdc at parodius.com |
>>>> | Parodius Networking                       http://www.parodius.com/ |
>>>> | UNIX Systems Administrator                  Mountain View, CA, USA |
>>>> | Making life hard for others since 1977.              PGP: 4BD6C0CB |
>>>>
>>>>
>>>>       
>>> _______________________________________________
>>> freebsd-hackers at freebsd.org mailing list
>>> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>>> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe at freebsd.org"
>>>     
>>
>>   
>
> _______________________________________________
> freebsd-hackers at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> To unsubscribe, send any mail to "freebsd-hackers-unsubscribe at freebsd.org"

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |