pthreads

[Neal H Walfield <neal@walfield.org>]

Hi all,

I am working on a pthread implementation to run under gnu mach for my
OS project this semester; expect to see some bits in the next month or
so.

Here is the problem that I have run into so far:

Background:

As a minimal implementation, I have a basic pthread_t, pthread_attr_t and
pthread_create.

When I try to link against the object that I create, I segmentation fault
_before_ I ever reach main:

Program received signal SIGSEGV, Segmentation fault.
0x0 in ?? ()
(gdb) bt
#0  0x0 in ?? ()
#1  0x115136b in __register_frame_info () from /lib/libc.so.0.2
#2  0x103c360 in __libc_global_ctors () from /lib/libc.so.0.2
#3  0x105e3e5 in posixland_init () from /lib/libc.so.0.2
#4  0x105e4b9 in init1 () from /lib/libc.so.0.2
#5  0x2ff1 in _dl_start_user () at rtld.c:142
(gdb) 

Even reducing the pthread_create routine to just a return yields the
same result.  Not calling pthread create in the test program also
yields the same result (ie only linking with the object).

Here is what I have determined so far.  There are pthread routines in
libc:

neal@hurd:/lib $ nm libc-2.1.2.so | grep pthread
         U pthread_create
         U pthread_getspecific
         U pthread_key_create
         U pthread_key_delete
         U pthread_mutex_lock
         U pthread_mutex_trylock
         U pthread_mutex_unlock
         U pthread_once
         U pthread_setspecific
neal@hurd:/lib $ 

o If I rename pthread_create to something else,  ie foo_pthread_create, it works
  fine.
o If I don't link against my object then I am fine (and not call
  pthread_create).
o If I call pthread create and don't link against the object (but supply my
  own header file for the prototypes), I get unresolved symbols.

Thanks in advance,
-Neal

-- 
----------------------------------------------------------------------------
Neal Walfield                                              neal@walfield.org
UMass Lowell - Fox 1512                                  Phone: 978-934-5347
                                                           Fax: 603-415-3645
Love is the triumph of imagination over intelligence.
                -- H. L. Mencken