Re: [Syllable-developer] Porting help

[Kristian V. D. V. <va...@li...>]

On Sun, 2008-10-26 at 04:16 +0100, Stefano D'Angelo wrote:
> 2008/10/24 Kristian Van Der Vliet <va...@li...>:
> > On Fri, 2008-10-24 at 13:31 +0100, Kristian Van Der Vliet wrote:
> >> I'll fix it in CVS later and email you a new libpthread if you like?
>  
> I will investigate on the remaining failures, in the meanwhile I
> noticed a couple of things:
> 
> - there seems to be no ldd script in Syllable - is this intentional?

Yes. The ldd script that is part of binutils uses ld.so, which we do not
have. Use readelf -d instead and look at the NEEDED items. The output
isn't as clear as ldd but shared libraries on Syllable rarely have
complex dependency trees.

> - the library you gave is name libpthread.so.2 while
> /system/libraries/libpthread.so linked to
> /system/libraries/libpthread.so.1 (using Syllable 0.6.5) - I guess
> this implies that my stuff will only work with Syllable >= 0.6.6?

Yes, but we do ship an ABI compatible libpthread.so.1 and I could &
should apply the same fix there.

> One of the two remaining problems goes like this:
>
> * the main thread allocates a mutex (ok)
> * another thread locks it (ok)
> * the same thread which locked it tries to unlock it, but
> pthread_mutex_unlock() returns EPERM
> 
> The mutex type is PTHREAD_MUTEX_ERRCHECK and it seems to always work
> this way.

Thanks, I'll look into it. Does it make any difference if the mutex is
not MUTEX_ERRCHECK?

> The last problem is a fault of mine... however I noticed that dlsym()
> sets errno to 131 when not finding some symbol (using strerror I get
> "Unknown error - 131", but I see it is ENOSYM in errno.h), which is
> probably fine since the POSIX standard doesn't seem to even mention
> errno is the dlsym page... however, in case you are interested in
> that, all other OSes I tried probably don't let dlsym set errno
> (Windows/MSYS, Linux, BSDs), while the AIX man page for dlsym states:
>
> "If the named symbol is found, its address is returned. If the named
> symbol is not found, NULL is returned and errno is set to 0."

Hmm, that's what it should be doing, but libdl does use the native call
get_symbol_address() which *may* set errno. libdl itself doesn't touch
errno, so it wont clear errno to zero if get_symbol_address() fails.

-- 
Vanders
http://www.syllable.org