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Re: Android/Termux pthread_cancel
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From: |
Bruno Haible |
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Subject: |
Re: Android/Termux pthread_cancel |
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Date: |
Fri, 11 May 2018 02:07:43 +0200 |
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User-agent: |
KMail/5.1.3 (Linux/4.4.0-119-generic; KDE/5.18.0; x86_64; ; ) |
Hi Paul,
> Thanks for the explanation. Does the attached Gnulib patch fix things for you?
The patch is surely good for Android. But the tricky part is to make sure
such a patch introduces no regression on the other platforms. And in fact,
this one does on FreeBSD 11, for the same reason we had to avoid 'phread_kill'
as witness symbol.
For this business of detecting whether libpthread is in use, we need to
consider all platforms on which USE_POSIX_THREADS_WEAK gets defined to 1.
These are:
A* Linux/glibc
B* Linux/musl
C* Hurd
D* GNU/kFreeBSD
E* FreeBSD, DragonFly
F* NetBSD
G* OpenBSD
H* HP-UX on ia64
I* IRIX
J* Solaris
K* Haiku
L* Android
So let's see in which library (libc vs. libpthread) the symbols are
defined.
Legend: C = libc, P = libpthread, - = not defined
A* B* C* D* E* F* G* H* I* J* K* L*
pthread_atfork P C P P P C - P P C C C
pthread_attr_destroy P C P P P P P P P P C C
pthread_attr_getdetachstate P C P P P P P P P P C C
pthread_attr_getguardsize P C P P P P - P P P C C
pthread_attr_getinheritsched P C P P P P P P P P - -
pthread_attr_getschedparam P C P P P P P P P P C C
pthread_attr_getschedpolicy P C P P P P P P P P - C
pthread_attr_getscope P C P P P P P P P P C C
pthread_attr_getstack P C P P P P P P - C - C
pthread_attr_getstackaddr P - P P P P P P P P - -
pthread_attr_getstacksize P C P P P P P P P P C C
pthread_attr_init P C P P P P P P P P C C
pthread_attr_setdetachstate P C P P P P P P P P C C
pthread_attr_setguardsize P C P P P P - P P P C C
pthread_attr_setinheritsched P C P P P P P P P P - -
pthread_attr_setschedparam P C P P P P P P P P C C
pthread_attr_setschedpolicy P C P P P P P P P P - C
pthread_attr_setscope P C P P P P P P P P C C
pthread_attr_setstack P C P P P P P P - C - C
pthread_attr_setstackaddr P - P P P P P P P P - -
pthread_attr_setstacksize P C P P P P P P P P C C
pthread_barrier_destroy P C P P P P - - - C C C
pthread_barrier_init P C P P P P - - - C C C
pthread_barrier_wait P C P P P P - - - C C C
pthread_barrierattr_destroy P C P P P P - - - C C C
pthread_barrierattr_init P C P P P P - - - C C C
pthread_barrierattr_setpshared P C P P P - - - - C C C
pthread_cancel P C P P P P P P P P C -
pthread_cond_broadcast P C P P P P P P P P C C
pthread_cond_destroy P C P P P P P P P P C C
pthread_cond_init P C P P P P P P P P C C
pthread_cond_signal P C P P P P P P P P C C
pthread_cond_timedwait P C P P P P P P P P C C
pthread_cond_wait P C P P P P P P P P C C
pthread_condattr_destroy P C P P P P P P P P C C
pthread_condattr_getpshared P C P P P - - P P P C C
pthread_condattr_init P C P P P P P P P P C C
pthread_condattr_setpshared P C P P P - - P P P C C
pthread_create P C P P P P P P P P C C
pthread_detach P C P P P P P P P P C C
pthread_equal P C P P P P P P P P C C
pthread_exit P C P P P P P P P P C C
pthread_getattr_np P C P P - - - - - - - C
pthread_getconcurrency P C P P P - P P P P C -
pthread_getcpuclockid P C P P - - - - - - - C
pthread_getschedparam P C P P P P P P P P C C
pthread_getspecific P C P P P P P P P P C C
pthread_join P C P P P P P P P P C C
pthread_key_create P C P P P P P P P P C C
pthread_key_delete P C P P P P P P P P C C
pthread_kill P C P P P P P P P P C C
pthread_kill_other_threads_np P - - P - - - - - - - -
pthread_mutex_destroy P C P P P P P P P P C C
pthread_mutex_init P C P P P P P P P P C C
pthread_mutex_lock P C P P P P P P P P C C
pthread_mutex_timedlock P C P P P - - - - C C C
pthread_mutex_trylock P C P P P P P P P P C C
pthread_mutex_unlock P C P P P P P P P P C C
pthread_mutexattr_destroy P C P P P P P P P P C C
pthread_mutexattr_getkind_np P - - P P - P - - - - -
pthread_mutexattr_getpshared P C P P P - - P P P C C
pthread_mutexattr_gettype P C P P P P P P P P C C
pthread_mutexattr_init P C P P P P P P P P C C
pthread_mutexattr_setkind_np P - - P P - P - - - - -
pthread_mutexattr_setpshared P C P P P - - P P P C C
pthread_mutexattr_settype P C P P P P P P P P C C
pthread_once P C P P P P P P P P C C
pthread_rwlock_destroy P C P P P P P P P P C C
pthread_rwlock_init P C P P P P P P P P C C
pthread_rwlock_rdlock P C P P P P P P P P C C
pthread_rwlock_timedrdlock P C P P P P - - - C C C
pthread_rwlock_timedwrlock P C P P P P - - - C C C
pthread_rwlock_tryrdlock P C P P P P P P P P C C
pthread_rwlock_trywrlock P C P P P P P P P P C C
pthread_rwlock_unlock P C P P P P P P P P C C
pthread_rwlock_wrlock P C P P P P P P P P C C
pthread_rwlockattr_destroy P C P P P P P P P P C C
pthread_rwlockattr_getkind_np P - - P - - - - - - - C
pthread_rwlockattr_getpshared P C P P P - P P P P C C
pthread_rwlockattr_init P C P P P P P P P P C C
pthread_rwlockattr_setkind_np P - - P - - - - - - - C
pthread_rwlockattr_setpshared P C P P P - P P P P C C
pthread_self P C P P P P P P P P C C
pthread_setcancelstate P C P P P P P P P P C -
pthread_setcanceltype P C P P P P P P P P C -
pthread_setconcurrency P C P P P - P P P P C -
pthread_setschedparam P C P P P P P P P P C C
pthread_setspecific P C P P P P P P P P C C
pthread_sigmask P C P P P P P P P P C C
pthread_spin_destroy P C P P P P - - - C C C
pthread_spin_init P C P P P P - - - C C C
pthread_spin_lock P C P P P P - - - C C C
pthread_spin_trylock P C P P P P - - - C C C
pthread_spin_unlock P C P P P P - - - C C C
pthread_testcancel P C P P P P P P P P C -
pthread_yield P - P P P - P P - - - -
I created this table using the attached data files (results of 'nm'
with a bit of post-processing) and this script:
for sym in `grep ^pthread_ glibc-2.3.6/libpthread`; do
pat="^${sym}\$";
if grep "$pat" glibc-2.3.6/libpthread >/dev/null; then a=P; else if grep
"$pat" glibc-2.3.6/libc >/dev/null; then a=C; else a=-; fi; fi;
if grep "$pat" musl/libc >/dev/null; then b=C; else b=-; fi;
if grep "$pat" hurd-0.9/libpthread >/dev/null; then c=P; else if grep "$pat"
hurd-0.9/libc >/dev/null; then c=C; else c=-; fi; fi;
if grep "$pat" glibc-2.13-kfreebsd/libpthread >/dev/null; then d=P; else if
grep "$pat" glibc-2.13-kfreebsd/libc >/dev/null; then d=C; else d=-; fi; fi;
if grep "$pat" freebsd-6.4/libpthread >/dev/null; then e=P; else if grep
"$pat" freebsd-6.4/libc >/dev/null; then e=C; else e=-; fi; fi;
if grep "$pat" netbsd-5.0.1/libpthread >/dev/null; then f=P; else if grep
"$pat" netbsd-5.0.1/libc >/dev/null; then f=C; else f=-; fi; fi;
if grep "$pat" openbsd-3.8/libpthread >/dev/null; then g=P; else if grep
"$pat" openbsd-3.8/libc >/dev/null; then g=C; else g=-; fi; fi;
if grep "$pat" hpux-11.31-ia64/libpthread >/dev/null; then h=P; else if grep
"$pat" hpux-11.31-ia64/libc >/dev/null; then h=C; else h=-; fi; fi;
if grep "$pat" irix-6.5/libpthread >/dev/null; then i=P; else if grep "$pat"
irix-6.5/libc >/dev/null; then i=C; else i=-; fi; fi;
if grep "$pat" solaris-2.10/libpthread >/dev/null; then j=P; else if grep
"$pat" solaris-2.10/libc >/dev/null; then j=C; else j=-; fi; fi;
if grep "$pat" haiku/libroot >/dev/null; then k=C; else k=-; fi;
if grep "$pat" android-9.0/libc >/dev/null; then l=C; else l=-; fi;
printf '%-32s%s %s %s %s %s %s %s %s %s %s %s %s\n' $sym $a $b $c
$d $e $f $g $h $i $j $k $l;
done
Now, for the !PTHREAD_IN_USE_DETECTION_HARD case, we need a symbol that is
- 'P' in the columns A*. C*, D*, E*, F*, G*, H*, I*, J*,
- not '-' in any column.
Also, we have to eliminate pthread_cancel and pthread_kill, because - as
the comment says - they got added to libc in newer versions of FreeBSD,
a fact that is not visible from the 'nm' results.
Result: 'pthread_cancel' won't do, because of the L* (Android) column - just
like Devin Hussey reported -, but any of the following symbols will do:
pthread_attr_destroy
pthread_attr_getdetachstate
pthread_attr_getschedparam
pthread_attr_getscope
pthread_attr_getstacksize
pthread_attr_init
pthread_attr_setdetachstate
pthread_attr_setschedparam
pthread_attr_setscope
pthread_attr_setstacksize
pthread_cond_broadcast
pthread_cond_destroy
pthread_cond_init
pthread_cond_signal
pthread_cond_timedwait
pthread_cond_wait
pthread_condattr_destroy
pthread_condattr_init
pthread_create
pthread_detach
pthread_equal
pthread_exit
pthread_getschedparam
pthread_getspecific
pthread_join
pthread_key_create
pthread_key_delete
pthread_mutex_destroy
pthread_mutex_init
pthread_mutex_lock
pthread_mutex_trylock
pthread_mutex_unlock
pthread_mutexattr_destroy
pthread_mutexattr_gettype
pthread_mutexattr_init
pthread_mutexattr_settype
pthread_once
pthread_rwlock_destroy
pthread_rwlock_init
pthread_rwlock_rdlock
pthread_rwlock_tryrdlock
pthread_rwlock_trywrlock
pthread_rwlock_unlock
pthread_rwlock_wrlock
pthread_rwlockattr_destroy
pthread_rwlockattr_init
pthread_self
pthread_setschedparam
pthread_setspecific
pthread_sigmask
If FreeBSD continues on their way (adding various implementations from
libpthread to libc), any symbol != pthread_create is a bit risky to use.
So, the best to use is pthread_create on all systems.
The reason I did not do that in the first place on 2018-02-17 was that
I didn't want to break other platforms. But now I have considered all
relevant platforms.
I tested this, and on IRIX 6.5 this change introduces a regression:
test-once1 succeeded before, and now crashes with
./test-once1: rld: Fatal Error: attempted access to unresolvable symbol in
./test-once1: pthread_once
The reason is that on IRIX, libc defines pthread_create (but not
pthread_cancel),
so the test (pthread_create != NULL) always evaluates to true.
So, the matrix above was incorrect. We need to consider also whether
a symbol is defined in libc, when it is defined in libpthread.
for sym in `grep ^pthread_ glibc-2.3.6/libpthread`; do
pat="^${sym}\$";
if grep "$pat" glibc-2.3.6/libpthread >/dev/null; then ap=P; else ap=-; fi;
if grep "$pat" glibc-2.3.6/libc >/dev/null; then a=C; else a=-; fi;
if grep "$pat" musl/libc >/dev/null; then b=C; else b=-; fi;
if grep "$pat" hurd-0.9/libpthread >/dev/null; then cp=P; else cp=-; fi;
if grep "$pat" hurd-0.9/libc >/dev/null; then c=C; else c=-; fi;
if grep "$pat" glibc-2.13-kfreebsd/libpthread >/dev/null; then dp=P; else
dp=-; fi;
if grep "$pat" glibc-2.13-kfreebsd/libc >/dev/null; then d=C; else d=-; fi;
if grep "$pat" freebsd-6.4/libpthread >/dev/null; then e1p=P; else e1p=-; fi;
if grep "$pat" freebsd-6.4/libc >/dev/null; then e1=C; else e1=-; fi;
if grep "$pat" freebsd-11.0/libpthread >/dev/null; then e2p=P; else e2p=-; fi;
if grep "$pat" freebsd-11.0/libc >/dev/null; then e2=C; else e2=-; fi;
if grep "$pat" netbsd-5.0.1/libpthread >/dev/null; then fp=P; else fp=-; fi;
if grep "$pat" netbsd-5.0.1/libc >/dev/null; then f=C; else f=-; fi;
if grep "$pat" openbsd-3.8/libpthread >/dev/null; then gp=P; else gp=-; fi;
if grep "$pat" openbsd-3.8/libc >/dev/null; then g=C; else g=-; fi;
if grep "$pat" hpux-11.31-ia64/libpthread >/dev/null; then hp=P; else hp=-;
fi;
if grep "$pat" hpux-11.31-ia64/libc >/dev/null; then h=C; else h=-; fi;
if grep "$pat" irix-6.5/libpthread >/dev/null; then ip=P; else ip=-; fi;
if grep "$pat" irix-6.5/libc >/dev/null; then i=C; else i=-; fi;
if grep "$pat" solaris-2.10/libpthread >/dev/null; then jp=P; else jp=-; fi;
if grep "$pat" solaris-2.10/libc >/dev/null; then j=C; else j=-; fi;
if grep "$pat" haiku/libroot >/dev/null; then k=C; else k=-; fi;
if grep "$pat" android-9.0/libc >/dev/null; then l=C; else l=-; fi;
printf '%-32s%s%s %s %s%s %s%s %s%s %s%s %s%s %s%s %s%s %s%s %s%s %s %s\n'
$sym $ap $a $b $cp $c $dp $d $e1p $e1 $e2p $e2 $fp $f $gp $g $hp $h $ip $i $jp
$j $k $l;
done
A* B* C* D* E1*E2*F* G* H* I* J* K* L*
pthread_atfork P- C P- P- P- PC -C -- PC P- -C C C
pthread_attr_destroy PC C PC PC P- PC P- P- PC PC PC C C
pthread_attr_getdetachstate PC C PC PC P- PC P- P- PC P- PC C C
pthread_attr_getguardsize P- C P- P- P- PC P- -- PC P- PC C C
pthread_attr_getinheritsched PC C PC PC P- PC P- P- PC P- PC - -
pthread_attr_getschedparam PC C PC PC P- PC P- P- PC P- PC C C
pthread_attr_getschedpolicy PC C PC PC P- PC P- P- PC P- PC - C
pthread_attr_getscope PC C PC PC P- PC P- P- PC P- PC C C
pthread_attr_getstack P- C P- P- P- P- P- P- P- -- -C - C
pthread_attr_getstackaddr P- - P- P- P- PC P- P- PC P- PC - -
pthread_attr_getstacksize P- C P- P- P- PC P- P- PC P- PC C C
pthread_attr_init PC C PC PC P- PC P- P- PC PC PC C C
pthread_attr_setdetachstate PC C PC PC P- PC P- P- PC PC PC C C
pthread_attr_setguardsize P- C P- P- P- PC P- -- PC P- PC C C
pthread_attr_setinheritsched PC C PC PC P- PC P- P- PC P- PC - -
pthread_attr_setschedparam PC C PC PC P- PC P- P- PC P- PC C C
pthread_attr_setschedpolicy PC C PC PC P- PC P- P- PC P- PC - C
pthread_attr_setscope PC C PC PC P- PC P- P- PC P- PC C C
pthread_attr_setstack P- C P- P- P- P- P- P- P- -- -C - C
pthread_attr_setstackaddr P- - P- P- P- PC P- P- PC PC PC - -
pthread_attr_setstacksize P- C P- P- P- PC P- P- PC PC PC C C
pthread_barrier_destroy P- C P- P- P- P- P- -- -- -- -C C C
pthread_barrier_init P- C P- P- P- P- P- -- -- -- -C C C
pthread_barrier_wait P- C P- P- P- P- P- -- -- -- -C C C
pthread_barrierattr_destroy P- C P- P- P- P- P- -- -- -- -C C C
pthread_barrierattr_init P- C P- P- P- P- P- -- -- -- -C C C
pthread_barrierattr_setpshared P- C P- P- P- P- -- -- -- -- -C C C
pthread_cancel P- C P- P- P- PC P- P- PC P- PC C -
pthread_cond_broadcast PC C PC PC PC PC P- P- PC PC PC C C
pthread_cond_destroy PC C PC PC PC PC P- P- PC PC PC C C
pthread_cond_init PC C PC PC PC PC P- P- PC PC PC C C
pthread_cond_signal PC C PC PC PC PC P- P- PC PC PC C C
pthread_cond_timedwait PC C PC PC P- PC P- P- PC PC PC C C
pthread_cond_wait PC C PC PC PC PC P- P- PC PC PC C C
pthread_condattr_destroy PC C PC PC P- P- P- P- PC P- PC C C
pthread_condattr_getpshared P- C P- P- P- P- -- -- PC P- PC C C
pthread_condattr_init PC C PC PC P- P- P- P- PC P- PC C C
pthread_condattr_setpshared P- C P- P- P- P- -- -- PC P- PC C C
pthread_create P- C P- P- P- P- P- P- PC PC PC C C
pthread_detach P- C P- P- P- PC P- P- PC P- PC C C
pthread_equal PC C PC PC P- PC P- P- PC P- PC C C
pthread_exit PC C PC PC P- PC P- P- PC PC PC C C
pthread_getattr_np P- C P- P- -- -- -- -- -- -- -- - C
pthread_getconcurrency P- C P- P- P- P- -- P- PC P- PC C -
pthread_getcpuclockid P- C P- P- -- P- -- -- -- -- -- - C
pthread_getschedparam PC C PC PC P- P- P- P- PC P- PC C C
pthread_getspecific P- C P- P- PC PC P- P- PC P- PC C C
pthread_join P- C P- P- P- PC P- P- PC P- PC C C
pthread_key_create P- C P- P- PC PC P- P- PC P- PC C C
pthread_key_delete P- C P- P- PC PC P- P- PC P- PC C C
pthread_kill P- C P- P- P- PC P- P- PC P- PC C C
pthread_kill_other_threads_np P- - -- P- -- -- -- -- -- -- -- - -
pthread_mutex_destroy PC C PC PC PC PC P- P- PC PC PC C C
pthread_mutex_init PC C PC PC PC PC P- P- PC PC PC C C
pthread_mutex_lock PC C PC PC PC PC P- P- PC PC PC C C
pthread_mutex_timedlock P- C P- P- P- P- -- -- -- -- -C C C
pthread_mutex_trylock P- C P- P- PC PC P- P- PC PC PC C C
pthread_mutex_unlock PC C PC PC PC PC P- P- PC PC PC C C
pthread_mutexattr_destroy P- C P- P- PC PC P- P- PC P- PC C C
pthread_mutexattr_getkind_np P- - -- P- P- P- -- P- -- -- -- - -
pthread_mutexattr_getpshared P- C P- P- P- P- -- -- PC P- PC C C
pthread_mutexattr_gettype P- C P- P- P- P- P- P- PC P- PC C C
pthread_mutexattr_init P- C P- P- PC PC P- P- PC P- PC C C
pthread_mutexattr_setkind_np P- - -- P- P- P- -- P- -- -- -- - -
pthread_mutexattr_setpshared P- C P- P- P- P- -- -- PC P- PC C C
pthread_mutexattr_settype P- C P- P- PC PC P- P- PC P- PC C C
pthread_once P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_destroy P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_init P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_rdlock P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_timedrdlock P- C P- P- P- P- P- -- -- -- -C C C
pthread_rwlock_timedwrlock P- C P- P- P- P- P- -- -- -- -C C C
pthread_rwlock_tryrdlock P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_trywrlock P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_unlock P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlock_wrlock P- C P- P- PC PC P- P- PC P- PC C C
pthread_rwlockattr_destroy P- C P- P- P- P- P- P- PC P- PC C C
pthread_rwlockattr_getkind_np P- - -- P- -- -- -- -- -- -- -- - C
pthread_rwlockattr_getpshared P- C P- P- P- P- -- P- PC P- PC C C
pthread_rwlockattr_init P- C P- P- P- P- P- P- PC P- PC C C
pthread_rwlockattr_setkind_np P- - -- P- -- -- -- -- -- -- -- - C
pthread_rwlockattr_setpshared P- C P- P- P- P- -- P- PC P- PC C C
pthread_self PC C PC PC PC PC P- P- PC PC PC C C
pthread_setcancelstate PC C PC PC P- PC P- P- PC P- PC C -
pthread_setcanceltype PC C PC PC P- PC P- P- PC P- PC C -
pthread_setconcurrency P- C P- P- P- P- -- P- PC P- PC C -
pthread_setschedparam PC C PC PC P- P- P- P- PC P- PC C C
pthread_setspecific P- C P- P- PC PC P- P- PC P- PC C C
pthread_sigmask P- C P- P- PC PC P- P- PC P- PC C C
pthread_spin_destroy P- C P- P- P- P- P- -- -- -- -C C C
pthread_spin_init P- C P- P- P- P- P- -- -- -- -C C C
pthread_spin_lock P- C P- P- P- P- P- -- -- -- -C C C
pthread_spin_trylock P- C P- P- P- P- P- -- -- -- -C C C
pthread_spin_unlock P- C P- P- P- P- P- -- -- -- -C C C
pthread_testcancel P- C P- P- P- PC P- P- PC PC PC C -
pthread_yield P- - P- P- P- P- -- P- P- -- -- - -
Now, for the !PTHREAD_IN_USE_DETECTION_HARD case, we need a symbol that is
- 'P-' in the columns A*. C*, D*, E1*, E2*, F*, G*, H*, I*, J*,
- not '-' or '--' in any column.
But this has no solution, not even 'pthread_cancel'. So apparently
'PC' needs to be allowed in the columns H* and J* ... The result is
this list of symbols:
pthread_mutexattr_gettype
pthread_rwlockattr_destroy
pthread_rwlockattr_init
I've tested this on all platforms listed above, except Android. I'm
pretty sure it works on Android as well.
2018-05-10 Bruno Haible <address@hidden>
lock, cond, thread, tls: Use a different symbol as libpthread witness.
Reported by Devin Hussey <address@hidden>.
Based on a patch by Paul Eggert.
* lib/glthread/lock.h (pthread_in_use): Use 'pthread_mutexattr_gettype'
as witness of libpthread.
* lib/glthread/cond.h (pthread_in_use): Likewise.
* lib/glthread/thread.h (pthread_in_use): Likewise.
* lib/glthread/tls.h (pthread_in_use): Likewise.
diff --git a/lib/glthread/cond.h b/lib/glthread/cond.h
index 54040ff..32a5f03 100644
--- a/lib/glthread/cond.h
+++ b/lib/glthread/cond.h
@@ -114,8 +114,8 @@ extern int glthread_in_use (void);
# endif
# if !PTHREAD_IN_USE_DETECTION_HARD
-# pragma weak pthread_cancel
-# define pthread_in_use() (pthread_cancel != NULL)
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() (pthread_mutexattr_gettype != NULL)
# endif
# else
diff --git a/lib/glthread/lock.h b/lib/glthread/lock.h
index dd8e1f8..c4251c3 100644
--- a/lib/glthread/lock.h
+++ b/lib/glthread/lock.h
@@ -149,18 +149,14 @@ extern int glthread_in_use (void);
# endif
# if !PTHREAD_IN_USE_DETECTION_HARD
- /* On most platforms, pthread_cancel or pthread_kill can be used to
- determine whether libpthread is in use.
- On newer versions of FreeBSD, however, this is no longer possible,
- because pthread_cancel and pthread_kill got added to libc. Therefore
- use pthread_create to test whether libpthread is in use. */
-# if defined __FreeBSD__ || defined __DragonFly__ /* FreeBSD */
-# pragma weak pthread_create
-# define pthread_in_use() (pthread_create != NULL)
-# else /* glibc, NetBSD, OpenBSD, IRIX, OSF/1, Solaris */
-# pragma weak pthread_cancel
-# define pthread_in_use() (pthread_cancel != NULL)
-# endif
+ /* Considering all platforms with USE_POSIX_THREADS_WEAK, only few symbols
+ can be used to determine whether libpthread is in use. These are:
+ pthread_mutexattr_gettype
+ pthread_rwlockattr_destroy
+ pthread_rwlockattr_init
+ */
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() (pthread_mutexattr_gettype != NULL)
# endif
# else
diff --git a/lib/glthread/thread.h b/lib/glthread/thread.h
index d8098c4..39a71de 100644
--- a/lib/glthread/thread.h
+++ b/lib/glthread/thread.h
@@ -149,8 +149,8 @@ extern int glthread_in_use (void);
# endif
# if !PTHREAD_IN_USE_DETECTION_HARD
-# pragma weak pthread_cancel
-# define pthread_in_use() (pthread_cancel != NULL)
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() (pthread_mutexattr_gettype != NULL)
# endif
# else
diff --git a/lib/glthread/tls.h b/lib/glthread/tls.h
index 12bf6d5..af1fb3b 100644
--- a/lib/glthread/tls.h
+++ b/lib/glthread/tls.h
@@ -76,8 +76,8 @@ extern int glthread_in_use (void);
# endif
# if !PTHREAD_IN_USE_DETECTION_HARD
-# pragma weak pthread_cancel
-# define pthread_in_use() (pthread_cancel != NULL)
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() (pthread_mutexattr_gettype != NULL)
# endif
# else
symlists.tar.gz
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