PTHREADS-WIN32 SNAPSHOT 2001-06-04
----------------------------------
Web Site: http://sources.redhat.com/pthreads-win32/
FTP Site: ftp://sources.redhat.com/pub/pthreads-win32
Coordinator: Ross Johnson <rpj@ise.canberra.edu.au>
We are pleased to announce the availability of a new snapshot of
Pthreads-win32, an Open Source Software (OSS) implementation of the
Threads component of the POSIX 1003.1c 1995 Standard for Microsoft's
Win32 environment. Some functions from POSIX 1003.1b are also
supported including semaphores. Other related functions include
the set of read-write lock functions.
Parts of the implementation also comply with the Open Group's
Unix 98 specification for compatibility with major Unix
implementations and Linux.
Pthreads-win32 is free software, distributed under the GNU Library
General Public License (LGPL).
Please see the 'Acknowledgements' section at the end of this
announcement for the list of contributors.
Change Summary (since the last snapshot)
----------------------------------------
(See the ChangeLog file for details.)
New:
- Async cancellation should now work for Windows running
on the following processors: IX86, MIPS, ALPHA, PPC.
- contributors name misplaced (please contact me if it's you)
- New functions (no-ops) for source code compatibility:
pthread_getconcurrency()
Returns the value previously set by
pthread_setconcurrency() or 0 (zero)
if no value was previously set.
The implementation does not currently use
this value.
pthread_setconcurrency()
Accepts any value >= 0 but does not
have any effect; returns '0' or
EINVAL if the value is < 0
pthread_attr_getscope()
pthread_attr_setscope()
Currently only return ENOSYS
- The following mutex types and related functions are now
supported:
pthread_mutexattr_gettype()
pthread_mutexattr_settype()
PTHREAD_MUTEX_DEFAULT
PTHREAD_MUTEX_NORMAL or PTHREAD_MUTEX_FAST_NP
PTHREAD_MUTEX_ERRORCHECK or PTHREAD_MUTEX_ERRORCHECK_NP
PTHREAD_MUTEX_RECURSIVE or PTHREAD_MUTEX_RECURSIVE_NP
The *_NP versions are for Linux portability.
In this implementation PTHREAD_MUTEX_DEFAULT is
mapped to PTHREAD_MUTEX_NORMAL for compatibility
with major Unix vendors. This is also the default
if no type is specified.
Please note that the default behaviour in previous
versions of the library was equivalent to
PTHREAD_MUTEX_RECURSIVE. This will be a problem
for some applications unless they are updated to
explicitly set the type of any mutexes that are, or
could be, locked recursively.
PTHREAD_MUTEX_NORMAL will cause thread deadlock
if the owner of a mutex tries to relock it without
first unlocking it. It has slightly less overhead
that other types.
- Thomas Pfaff <tpfaff@gmx.net>
- Pthreads-win32 mutexes are now based on Win32
critical sections for all Windows versions. The
implementation no longer depends on
TryEnterCriticalSection.
- Thomas Pfaff <tpfaff@gmx.net>
- New implementation of condition variables which attempts to
correct problems of spurious wakeups, unfairness, and
broadcast deadlock. See README.CV for details of the
discussion.
- Alexander Terekhov <TEREKHOV@de.ibm.com>
- Louis Thomas <lthomas@arbitrade.com>
Bugs fixed:
- Pthread_mutex_trylock() now properly returns EBUSY
even when the current thread owns the mutex.
Consequently, pthread_mutex_destroy() will no longer
destroy a locked mutex (it will return EBUSY).
- Thomas Pfaff <tpfaff@gmx.net>
- Errno warnings and building with /MD;
calling conventions (stdcall v cdecl);
thread termination problems;
- Milan Gardian <Milan.Gardian@LEIBINGER.com>
Known bugs in this snapshot
---------------------------
1. Under MS VC++ (only tested with version 6.0), a term_func
set via the standard C++ set_terminate() function is not called
for some reason. The code - in private.c:ptw32_threadStart() -
makes an explicit call to terminate() which works as expected
under MinGW32 g++ doesn't appear to run the term_func under
MC VC++ 6.0.
2. Cancellation problems in optimised code
- Milan Gardian
The cancellation (actually, cleanup-after-cancel) tests fail when using VC
(professional) optimisation switches (/O1 or /O2) in pthreads library. I
have not investigated which concrete optimisation technique causes this
problem (/Og, /Oi, /Ot, /Oy, /Ob1, /Gs, /Gf, /Gy, etc.), but here is a
summary of builds and corresponding failures:
* pthreads VSE (optimised tests): OK
* pthreads VCE (optimised tests): Failed "cleanup1" test (runtime)
* pthreads VSE (DLL in CRT, optimised tests): OK
* pthreads VCE (DLL in CRT, optimised tests): Failed "cleanup1" test
(runtime)
Please note that while in VSE version of the pthreads library the
optimisation does not really have any impact on the tests (they pass OK), in
VCE version addition of optimisation (/O2 in this case) causes the tests to
fail uniformly - either in "cleanup0" or "cleanup1" test cases.
Please note that all the tests above use default pthreads DLL (no
optimisations, linked with either static or DLL CRT, based on test type).
Therefore the problem lies not within the pthreads DLL but within the
compiled client code (the application using pthreads -> involvement of
"pthread.h").
I think the message of this section is that usage of VCE version of pthreads
in applications relying on cancellation/cleanup AND using optimisations for
creation of production code is highly unreliable for the current version of
the pthreads library.
Caveats
-------
1. Due to what is believed to be a C++ compliance error in VC++,
if your application contains catch(...) blocks in your POSIX threads
then you will need to replace the "catch(...)" with the macro
"PtW32Catch", eg.
#ifdef PtW32Catch
PtW32Catch {
...
}
#else
catch(...) {
...
}
#endif
Otherwise neither pthreads cancelation nor pthread_exit() will work
reliably.
Level of standards conformance
------------------------------
The following POSIX 1003.1c 1995 options are defined:
_POSIX_THREADS
_POSIX_THREAD_SAFE_FUNCTIONS
_POSIX_THREAD_ATTR_STACKSIZE
The following POSIX 1003.1c 1995 options are not defined:
_POSIX_THREAD_ATTR_STACKADDR
_POSIX_THREAD_PRIORITY_SCHEDULING
_POSIX_THREAD_PRIO_INHERIT
_POSIX_THREAD_PRIO_PROTECT
_POSIX_THREAD_PROCESS_SHARED
The following POSIX 1003.1b option is defined:
_POSIX_SEMAPHORES
The following functions are implemented:
---------------------------
PThreads
---------------------------
pthread_attr_init
pthread_attr_destroy
pthread_attr_getdetachstate
pthread_attr_getstackaddr
pthread_attr_getstacksize
pthread_attr_setdetachstate
pthread_attr_setstackaddr
pthread_attr_setstacksize
pthread_create
pthread_detach
pthread_equal
pthread_exit
pthread_join
pthread_once
pthread_self
pthread_cancel
pthread_cleanup_pop
pthread_cleanup_push
pthread_setcancelstate
pthread_setcanceltype
pthread_testcancel
---------------------------
Thread Specific Data
---------------------------
pthread_key_create
pthread_key_delete
pthread_setspecific
pthread_getspecific
---------------------------
Mutexes
---------------------------
pthread_mutexattr_init
pthread_mutexattr_destroy
pthread_mutexattr_getpshared
pthread_mutexattr_setpshared
pthread_mutexattr_gettype
pthread_mutexattr_settype (types: PTHREAD_MUTEX_DEFAULT
PTHREAD_MUTEX_NORMAL
PTHREAD_MUTEX_ERRORCHECK
PTHREAD_MUTEX_RECURSIVE )
pthread_mutex_init
pthread_mutex_destroy
pthread_mutex_lock
pthread_mutex_trylock
pthread_mutex_unlock
---------------------------
Condition Variables
---------------------------
pthread_condattr_init
pthread_condattr_destroy
pthread_condattr_getpshared
pthread_condattr_setpshared
pthread_cond_init
pthread_cond_destroy
pthread_cond_wait
pthread_cond_timedwait
pthread_cond_signal
pthread_cond_broadcast
---------------------------
Read/Write Locks:
---------------------------
pthread_rwlock_init
pthread_rwlock_destroy
pthread_rwlock_tryrdlock
pthread_rwlock_trywrlock
pthread_rwlock_rdlock
pthread_rwlock_rwlock
pthread_rwlock_unlock
---------------------------
Semaphores
---------------------------
sem_init (POSIX 1b)
sem_destroy (POSIX 1b)
sem_post (POSIX 1b)
sem_wait (POSIX 1b)
sem_trywait (POSIX 1b)
sem_open (POSIX 1b - returns an error ENOSYS)
sem_close (POSIX 1b - returns an error ENOSYS)
sem_unlink (POSIX 1b - returns an error ENOSYS)
sem_getvalue (POSIX 1b - returns an error ENOSYS)
---------------------------
RealTime Scheduling
---------------------------
pthread_attr_getschedparam
pthread_attr_setschedparam
pthread_getschedparam
pthread_setschedparam
pthread_getconcurrency (always returns '0' indicating system default)
pthread_setconcurrency (accepts any value >= 0 but is ignored)
pthread_attr_getscope (returns an error ENOSYS)
pthread_attr_setscope (returns an error ENOSYS)
sched_get_priority_max (POSIX 1b)
sched_get_priority_min (POSIX 1b)
sched_yield (POSIX 1b)
---------------------------
Signals
---------------------------
pthread_sigmask
---------------------------
Non-portable routines (see the README.NONPORTABLE file for usage)
---------------------------
pthread_getw32threadhandle_np
pthread_delay_np
pthread_mutexattr_getkind_np
pthread_mutexattr_setkind_np (types: PTHREAD_MUTEX_FAST_NP,
PTHREAD_MUTEX_ERRORCHECK_NP,
PTHREAD_MUTEX_RECURSIVE_NP)
pthread_win32_process_attach_np
pthread_win32_process_detach_np
pthread_win32_thread_attach_np
pthread_win32_thread_detach_np
---------------------------
Static Initializers (macros)
---------------------------
PTHREAD_ONCE_INIT
PTHREAD_MUTEX_INITIALIZER
PTHREAD_COND_INITIALIZER
PTHREAD_RWLOCK_INITIALIZER
---------------------------
Thread-Safe C Runtime Library (macros)
---------------------------
strtok_r
asctime_r
ctime_r
gmtime_r
localtime_r
rand_r
The following functions are not implemented:
---------------------------
RealTime Scheduling
---------------------------
pthread_attr_getinheritsched
pthread_attr_getschedpolicy
pthread_attr_setinheritsched
pthread_attr_setschedpolicy
pthread_mutex_getprioceiling
pthread_mutex_setprioceiling
pthread_mutex_attr_getprioceiling
pthread_mutex_attr_getprotocol
pthread_mutex_attr_setprioceiling
pthread_mutex_attr_setprotocol
---------------------------
Fork Handlers
---------------------------
pthread_atfork
---------------------------
Stdio
---------------------------
flockfile
ftrylockfile
funlockfile
getc_unlocked
getchar_unlocked
putc_unlocked
putchar_unlocked
---------------------------
Thread-Safe C Runtime Library
---------------------------
readdir_r
getgrgid_r
getgrnam_r
getpwuid_r
getpwnam_r
---------------------------
Signals
---------------------------
pthread_kill
sigtimedwait
sigwait
sigwaitinfo
The library includes two non-API functions for creating cancellation
points in applications and libraries:
pthreadCancelableWait
pthreadCancelableTimedWait
Availability
------------
The prebuilt DLL, export libs (for both MSVC and Mingw32), and the header
files (pthread.h, semaphore.h, sched.h) are available along with the
complete source code.
The source code can be found at:
ftp://sources.redhat.com/pub/pthreads-win32
and as individual source code files at
ftp://sources.redhat.com/pub/pthreads-win32/source
The pre-built DLL, export libraries and include files can be found at:
ftp://sources.redhat.com/pub/pthreads-win32/dll-latest
Mailing List
------------
There is a mailing list for discussing pthreads on Win32. To join,
send email to:
pthreads-win32-subscribe@sourceware.cygnus.com
Application Development Environments
------------------------------------
MSVC:
MSVC using SEH works. Distribute pthreadVSE.dll with your application.
MSVC using C++ EH works. Distribute pthreadVCE.dll with your application.
Mingw32:
You need gcc-2.95.2-1 modified as per pthreads-win32 FAQ answer (6), with
binutils-19990818-1 and msvcrt runtime-2000-03-27. Mingw32 must use
the thread-safe MSVCRT library (see the FAQ). You need to distribute
the gcc.dll DLL from Mingw32 with your application (as well as
pthreadGCE.dll of course).
Cygwin: (http://sourceware.cygnus.com/cygwin/)
Cygwin aims to provide a complete POSIX environment on top of Win32, including
threads. When this is complete, developers using Cygwin will not need
pthreads-win32. At this time, Cygwin has preliminary support for multithreaded
development, however, this is not turned on by default. We have not tested
pthreads-win32 against Cygwin.
UWIN:
UWIN is a complete Unix-like environment for Windows from AT&T. Pthreads-win32
doesn't currently support UWIN (and vice versa), but that may change in the
future.
Generally:
For convenience, the following pre-built files are available on the FTP site
(see Availability above):
pthread.h - for POSIX 1c threads
semaphore.h - for POSIX 1b semaphores
sched.h - for POSIX 1b scheduling
pthreadVCE.dll - built with MSVC++ compiler using C++ EH
pthreadVCE.lib
pthreadVSE.dll - built with MSVC compiler using SEH
pthreadVSE.lib
pthreadGCE.dll - built with Mingw32 G++ 2.95.2-1
libpthreadw32.a - derived from pthreadGCE.dll
These are the only files you need in order to build POSIX threads
applications for Win32 using either MSVC or Mingw32.
See the FAQ file in the source tree for additional information.
Building the library with MSVC from source
------------------------------------------
A simple makefile for building the library with MSVC is available. Just
run nmake in a command shell in the pthreads source directory for targets
to make either the VSE or VCE version of the library. Eg:
cd <PTHREADS_ROOT>\pthreads
nmake clean VSE
or
nmake clean VCE
There are currently no nmake targets to make statically linked
versions of the library.
Building the library with MinGW32 from source
---------------------------------------------
Run make in the pthreads source directory. Ie:
cd <PTHREADS_ROOT>\pthreads
make clean
make
The GNU make utility will find the GNUmakefile in the pthreads source
directory.
Documentation
-------------
Currently, there is no documentation included in the package apart
from the copious comments in the source code.
For POSIX Thread API programming, several reference books are
available:
Programming with POSIX Threads
David R. Butenhof
Addison-Wesley (pub)
Pthreads Programming
By Bradford Nichols, Dick Buttlar & Jacqueline Proulx Farrell
O'Reilly (pub)
Acknowledgements
----------------
This library is based substantially on a Win32 pthreads
implementation contributed by John Bossom <John.Bossom@cognos.com>.
The implementation of condition variables is derived from the work
of Douglas Schmidt et al
(http://www.cs.wustl.edu/~schmidt/win32-cv-1.html).
There is also a separate CONTRIBUTORS file. This file and others are
on the web site:
http://sources.redhat.com/pthreads-win32
Enjoy!
Ross Johnson