npth finds pthread_mutex_timedlock() which android does not have

[Marcus Brinkmann]

On 03/10/2012 04:52 AM, Hans-Christoph Steiner wrote:
> Unfortunately, the Android linker doesn't give you much info, but you
> can get more info using ld.  I copied all of the android-2.2 .so files
> into /tmp and did this:
>
> $ arm-linux-androideabi-ld --rpath=/tmp libnpth.so
> arm-linux-androideabi-ld: warning: cannot find entry symbol _start;
> defaulting to 00008248
> libnpth.so: undefined reference to `pthread_rwlock_rdlock'
> libnpth.so: undefined reference to `pthread_rwlock_timedwrlock'
> libnpth.so: undefined reference to `pthread_rwlock_timedrdlock'
> libnpth.so: undefined reference to `pthread_rwlock_wrlock'
> libnpth.so: undefined reference to `pthread_rwlock_trywrlock'
> libnpth.so: undefined reference to `pthread_rwlock_tryrdlock'

Did you build npth against API level < 9?  You can't use the API level 
 >= 9 builds of npth on earlier androids, because for those I enable the 
rwlock usage.  If there is a general expectation in the Android 
community that you can install builds against later API levels on 
earlier devices, we may change that.  Is that the case?

I tried building gnupg-for-android in the following way, and did not see 
any dangling rwlock related references in libnpth.so:

$ make -C external NDK_BASE=/.../android-ndk-r7b NDK_PLATFORM_LEVEL=8 
gnupg-install

$ arm-linux-androideabi-objdump --dynamic-syms libnpth.so.0.0.0 |grep 
'*UND*' | grep pthread_
00000000      DF *UND*	00000000              pthread_create
00000000      DF *UND*	00000000              pthread_exit
00000000      DF *UND*	00000000              pthread_sigmask
00000000      DF *UND*	00000000              pthread_self
00000000      DF *UND*	00000000              pthread_mutex_lock
00000000      DF *UND*	00000000              pthread_cond_wait
00000000      DF *UND*	00000000              pthread_mutex_trylock
00000000      DF *UND*	00000000              pthread_join
00000000      DF *UND*	00000000              pthread_cond_timedwait

If you did build against 8 and it still has undefined references, 
something is not working right.  Here is what is supposed to happen:

In npth/src/npth.h, I check the API level of Android, if it is < 9, I 
define _NPTH_NO_RWLOCK and define all npth_rwlock functions and types to 
equivalent mutex types or dummies.

Also, if _NPTH_NO_RWLOCK is defined, in src/npth.c, no functions using 
pthread_rwlock are defined.

If this isn't working for you, maybe you can find out what's going wrong?

Thanks,
Marcus