valgrind-users

[Valgrind-users] Need a configure check for NPTL

[Julian S. <js...@ac...>]

Greetings, all.

I'm trying to add support to V for R H 9, and it nearly works.

I need a configure (autoconf, etc) check to establish whether 
V is being built on a system which uses NPTL (Native Posix
Threads Library) as opposed to the older LinuxThreads library.

So far R H 9 is the only distro I'm aware of that uses NPTL.

Problem is: I have a set of patches which does appear to make
V work on R H 9, but they break all other systems.  So I need
a configure test to distinguish NPTL-based systems from
LinuxThreads-based systems.

Anyone have a reliable check easily to hand?

J

Re: [Valgrind-users] Need a configure check for NPTL

[Robert W. <rj...@du...>]

> Anyone have a reliable check easily to hand?

Yeugh.  I don't know if this is reliable, but pthread_tryjoin_np is
implemented in nptl but not in the original pthread stuff.  Perhaps a
check for that will let you know?  It will certainly let you know if
pthread_tryjoin_np is implemented, but you might allow yourself to infer
from that that it's nptl... :-)

Regards,
 Robert.

--=20
Robert Walsh
Amalgamated Durables, Inc.  -  "We don't make the things you buy."
Email: rj...@du...

Re: [Valgrind-users] Need a configure check for NPTL

[Julian S. <js...@ac...>]

On Sunday 06 April 2003 6:48 pm, Robert Walsh wrote:
> > Anyone have a reliable check easily to hand?
>
> Yeugh.  I don't know if this is reliable, but pthread_tryjoin_np is
> implemented in nptl but not in the original pthread stuff.  Perhaps a
> check for that will let you know?  It will certainly let you know if
> pthread_tryjoin_np is implemented, but you might allow yourself to infer
> from that that it's nptl... :-)

Hmm.  Sounds a plausible scheme, but ...

On the one hand (on RH 9),   nm /lib/tls/libpthread.so.0 | grep tryjoin
shows pthread_tryjoin_np as an exported text symbol ("T").

On the other hand, you can't link against it:

   sewardj@localhost:~/VgHEAD/valgrind$ cat nptltest.c

   #include <pthread.h>
   extern int pthread_tryjoin_np;
   int main (int argc, char * argv )
   {
      int* p = (int*)(& pthread_tryjoin_np);
      return 0;
   }

   sewardj@localhost:~/VgHEAD/valgrind$ gcc -o nptltest nptltest.c -lpthread
   /tmp/ccWjnvw9.o(.text+0x13): In function `main':
   : undefined reference to `pthread_tryjoin_np'
   collect2: ld returned 1 exit status

Now what?  If the symbol is in the DSO, why can't I link to it?
Mystified.

J

Re: [Valgrind-users] Need a configure check for NPTL

[Robert W. <rj...@du...>]

> Now what?  If the symbol is in the DSO, why can't I link to it?
> Mystified.

You seem to be saying "Mystified" a lot about the NPTL :-)  This does
seem strange, though.  Are you sure you're picking up the correct
library?  Maybe you need to say "extern int pthread_join_np();" instead
of just "extern int pthread_join_np;" (i.e. declare it as an external
function and not variable.)  I haven't checked, so this may be a red
herring.

BTW: my file-descriptor leakage support is almost ready.  I'm just
testing the "passing fds over a unix-domain socket" support at the
moment.  Sockets are weird.

Regards,
 Robert.

--=20
Robert Walsh
Amalgamated Durables, Inc.  -  "We don't make the things you buy."
Email: rj...@du...

Re: [Valgrind-users] Need a configure check for NPTL

[Biswapesh C. <bis...@tc...>]

IIRC, the wine folks have a reasonable configure time check for NPTL in
CVS, so maybe you can simply swipe their code ?

Of course, the issue they are facing is that what if the program
(wine/valgrind) is compiled with one kind of threading support and the
binary shipped to a system with a different type of threading ?
Basically, in that case, you need a runtime check as well.

> On Sunday 06 April 2003 6:48 pm, Robert Walsh wrote:
> > > Anyone have a reliable check easily to hand?
> >
> > Yeugh.  I don't know if this is reliable, but pthread_tryjoin_np is
> > implemented in nptl but not in the original pthread stuff.  Perhaps a
> > check for that will let you know?  It will certainly let you know if
> > pthread_tryjoin_np is implemented, but you might allow yourself to infer
> > from that that it's nptl... :-)
> 
> Hmm.  Sounds a plausible scheme, but ...
> 
> On the one hand (on RH 9),   nm /lib/tls/libpthread.so.0 | grep tryjoin
> shows pthread_tryjoin_np as an exported text symbol ("T").
> 
> On the other hand, you can't link against it:
> 
>    sewardj@localhost:~/VgHEAD/valgrind$ cat nptltest.c
> 
>    #include <pthread.h>
>    extern int pthread_tryjoin_np;
>    int main (int argc, char * argv )
>    {
>       int* p = (int*)(& pthread_tryjoin_np);
>       return 0;
>    }
> 
>    sewardj@localhost:~/VgHEAD/valgrind$ gcc -o nptltest nptltest.c
>    -lpthread
>    /tmp/ccWjnvw9.o(.text+0x13): In function `main':
>    : undefined reference to `pthread_tryjoin_np'
>    collect2: ld returned 1 exit status
> 
> Now what?  If the symbol is in the DSO, why can't I link to it?
> Mystified.
> 
> J
> 
> 
> 
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-- 
Biswa.

Re: [Valgrind-users] Need a configure check for NPTL

[Robert W. <rj...@du...>]

> IIRC, the wine folks have a reasonable configure time check for NPTL in
> CVS, so maybe you can simply swipe their code ?

I can't find that.  I can see a --with-nptl switch, but no automated
check.  If doing it the automated way is too difficult, maybe having a
--with-nptl switch is the way to go?

Regards,
 Robert.

--=20
Robert Walsh
Amalgamated Durables, Inc.  -  "We don't make the things you buy."
Email: rj...@du...