Seg fault with libstdc++-v3 and pthreads

[Moore, David]

Hi,

I found your post (below) on the libstdc++-v3 mailing list archive.  I was
also trying to use the libstdc++-v3 with pthreads, with the same result.

I would greatly appreciate knowing - were you able to find a way around this
problem, or is there no solution at this stage of the libstdc++ development?

Thanks,
David Moore.


---------------------------------------------------------------------------
Tue, 23 Nov 1999


Greetings!

I know that stdlibc++ is not thread safe at the moment, but does this
implie the following behaviour?

The following code crashes in the initialization phase with Segmentation
fault. Without libstdc++ the program runs correct and returns 42.

Environment: stdlibc++ (CVS1999-11-19), gcc2.95.2, Linux 2.2.10:
--Code------------------------------------
#include <iostream>
#include <pthread.h>

struct foo {
  pthread_mutex_t lock;
  foo(){ pthread_mutex_init(&lock, 0); };
  int bar(void);
};

int foo::bar(void)
{
  pthread_mutex_lock(&lock);
  // do something that should be locked
  pthread_mutex_unlock(&lock);
  return 42;
}

int main() 
{
  foo a;
  cout << a.bar() << endl;
}
--Code end------------------------------------

It was compiled this way:

g++ -c -pipe -Wall -g -pthread -I../../lib -I/opt/libstdc++/include/g++-v3
-o test.o test.cc
g++ -pthread -static -o test test.o  -L/opt/libstdc++/lib 

and this is the gdb backtrace:

Program received signal SIGSEGV, Segmentation fault.
__pthread_mutex_init (mutex=0x0, mutex_attr=0xbffff744) at mutex.c:29
29      mutex.c: No such file or directory.
Current language:  auto; currently c
(gdb) bt
#0  __pthread_mutex_init (mutex=0x0, mutex_attr=0xbffff744) at mutex.c:29
#1  0x808dc84 in _IO_init (fp=0x80fcf28, flags=0) at genops.c:556
#2  0x806c06f in __basic_file::__basic_file (this=0x80fcf28)
    at ../../libstdc++/src/basic_file.cc:41
#3  0x805c99f in basic_filebuf<char, char_traits<char> >::_M_init_filebuf
(
    this=0x80fa9e0) at ../../libstdc++/bits/fstream.tcc:48
#4  0x805cad6 in basic_filebuf<char, char_traits<char> >::basic_filebuf (
    this=0x80fa9e0) at ../../libstdc++/bits/fstream.tcc:61
#5  0x80496da in __static_initialization_and_destruction_0
(__initialize_p=1,
    __priority=65535) at ../../libstdc++/src/stdstreams.cc:35
#6  0x804987d in global constructors keyed to __cfileinit ()
    at ../../libstdc++/bits/std_istream.h:70
#7  0x80b95d9 in __do_global_ctors_aux () at cp/tinfo.h:50
#8  0x80480ea in _init ()
#9  0x8079007 in __libc_start_main (main=0x8048200 <main>, argc=1,
    argv=0xbffff894, init=0x80480c0 <_init>, fini=0x80c9920 <_fini>,
    rtld_fini=0, stack_end=0xbffff88c) at
../sysdeps/generic/libc-start.c:83
(gdb)

Any idea what's going wrong here?

Thanks in advance

Gerwin

Gerwin Pfab <pb@schenk.isar.de>   Dr. Schenk Industriemesstechnik GmbH
Dipl. Ing.                        Einsteinstrasse 37 
Software Engineering              D-82152 Martinsried
                                  Tel: +49-89-85695-0
                                  Fax: +49-89-85695-200