Hi, while porting the threaded qt-3 release to cygwin, it seems to me, that there is a bug in the current pthread implementation.
The problem: Parts of the qt-3 thread initialisation code (which works under linux) look like below: <snip> pthread_mutexattr_t attr; pthread_mutexattr_init(&attr); <snip> which lets attr undefined. In the example with gcc (2.59.3-5)/ld the (stack-)content is 0xc, which lets pthread_mutexattr_init() crash. A look into the code shows: __pthread_mutexattr_init (pthread_mutexattr_t *attr) { [1] if (pthread_mutexattr::isGoodObject (attr)) // calls -> verifyable_object_isvalid -> check_valid_pointer ->IsBadWritePtr(*attr) -> segfault!! [1] return EBUSY; *attr = new pthread_mutexattr (); if (!pthread_mutexattr::isGoodObject (attr)) { delete (*attr); *attr = NULL; return ENOMEM; } return 0; } The definition of this functions in http://www.opengroup.org/onlinepubs/007904975/functions/pthread_mutexattr_init.h tml tells me, that pthread_mutexattr_init() should initialise attr, but how should attr be a good object [1], when pthread_mutexattr_init hasn't done any initialisation. This seems to me as a violation of the definition. further details verifyable_object_state verifyable_object_isvalid (void const * objectptr, long magic, void *static_ptr) { verifyable_object **object = (verifyable_object **)objectptr; if (check_valid_pointer (object)) return INVALID_OBJECT; if (static_ptr && *object == static_ptr) return VALID_STATIC_OBJECT; if (!*object) return INVALID_OBJECT; if (check_valid_pointer (*object)) return INVALID_OBJECT; ^^^^^^ here it crashes if ((*object)->magic != magic) return INVALID_OBJECT; return VALID_OBJECT; } The following patch seems to fix this, but I'm not sure, if I have overseen something. $ cvs diff -p thread.cc Index: thread.cc =================================================================== RCS file: /cvs/src/src/winsup/cygwin/thread.cc,v retrieving revision 1.106 diff -u -3 -p -B -p -r1.106 thread.cc --- thread.cc 24 Nov 2002 13:54:14 -0000 1.106 +++ thread.cc 30 Nov 2002 01:24:04 -0000 @@ -2416,8 +2416,8 @@ __pthread_mutexattr_init (pthread_mu int __pthread_mutexattr_init (pthread_mutexattr_t *attr) { - if (pthread_mutexattr::isGoodObject (attr)) - return EBUSY; + if (check_valid_pointer (attr)) + return EINVAL; *attr = new pthread_mutexattr (); if (!pthread_mutexattr::isGoodObject (attr)) --------------------------------------------------------------------- 2002-11-30 Ralf Habacker <[EMAIL PROTECTED]> * thread.cc (__pthread_mutexattr_init ): fixed seg fault if parameter content is undefined. Hops that help Ralf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/