Game Programming - All in One (3rd Edition)

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Text File | 2003-09-18 | 19.0 KB | 534 lines

SNAPSHOT 2003-09-18 ------------------- Cleanup of thread priority management. In particular, setting of thread priority now attempts to map invalid Win32 values within the range returned by sched_get_priority_min/max() to useful values. See README.NONPORTABLE under "Thread priority". Bug fixes --------- * pthread_getschedparam() now returns the priority given by the most recent call to pthread_setschedparam() or established by pthread_create(), as required by the standard. Previously, pthread_getschedparam() incorrectly returned the running thread priority at the time of the call, which may have been adjusted or temporarily promoted/demoted. * sched_get_priority_min() and sched_get_priority_max() now return -1 on error and set errno. Previously, they incorrectly returned the error value directly. SNAPSHOT 2003-09-04 ------------------- Bug fixes --------- * ptw32_cancelableWait() now allows cancelation of waiting implicit POSIX threads. New test -------- * cancel8.c tests cancelation of Win32 threads waiting at a POSIX cancelation point. SNAPSHOT 2003-09-03 ------------------- Bug fixes --------- * pthread_self() would free the newly created implicit POSIX thread handle if DuplicateHandle failed instead of recycle it (very unlikely). * pthread_exit() was neither freeing nor recycling the POSIX thread struct for implicit POSIX threads. New feature - Cancelation of/by Win32 (non-POSIX) threads --------------------------------------------------------- Since John Bossom's original implementation, the library has allowed non-POSIX initialised threads (Win32 threads) to call pthreads-win32 routines and therefore interact with POSIX threads. This is done by creating an on-the-fly POSIX thread ID for the Win32 thread that, once created, allows fully reciprical interaction. This did not extend to thread cancelation (async or deferred). Now it does. Any thread can be canceled by any other thread (Win32 or POSIX) if the former thread's POSIX pthread_t value is known. It's TSD destructors and POSIX cleanup handlers will be run before the thread exits with an exit code of PTHREAD_CANCELED (retrieved with GetExitCodeThread()). This allows a Win32 thread to, for example, call POSIX CV routines in the same way that POSIX threads would/should, with pthread_cond_wait() cancelability and cleanup handlers (pthread_cond_wait() is a POSIX cancelation point). By adding cancelation, Win32 threads should now be able to call all POSIX threads routines that make sense including semaphores, mutexes, condition variables, read/write locks, barriers, spinlocks, tsd, cleanup push/pop, cancelation, pthread_exit, scheduling, etc. Note that these on-the-fly 'implicit' POSIX thread IDs are initialised as detached (not joinable) with deferred cancelation type. The POSIX thread ID will be created automatically by any POSIX routines that need a POSIX handle (unless the routine needs a pthread_t as a parameter of course). A Win32 thread can discover it's own POSIX thread ID by calling pthread_self(), which will create the handle if necessary and return the pthread_t value. New tests --------- Test the above new feature. SNAPSHOT 2003-08-19 ------------------- This snapshot fixes some accidental corruption to new test case sources. There are no changes to the library source code. SNAPSHOT 2003-08-15 ------------------- Bug fixes --------- * pthread.dsp now uses correct compile flags (/MD). - Viv <vcotirlea@hotmail.com> * pthread_win32_process_detach_np() fixed memory leak. - Steven Reddie <Steven.Reddie@ca.com> * pthread_mutex_destroy() fixed incorrect return code. - Nicolas Barry <boozai@yahoo.com> * pthread_spin_destroy() fixed memory leak. - Piet van Bruggen <pietvb@newbridges.nl> * Various changes to tighten arg checking, and to work with later versions of MinGW32 and MsysDTK. * pthread_getschedparam() etc, fixed dangerous thread validity checking. - Nicolas Barry <boozai@yahoo.com> * POSIX thread handles are now reused and their memory is not freed on thread exit. This allows for stronger thread validity checking. New standard routine -------------------- * pthread_kill() added to provide thread validity checking to applications. It does not accept any non zero values for the signal arg. New test cases -------------- * New test cases to confirm validity checking, pthread_kill(), and thread reuse. SNAPSHOT 2003-05-10 ------------------- Bug fixes --------- * pthread_mutex_trylock() now returns correct error values. pthread_mutex_destroy() will no longer destroy a recursively locked mutex. pthread_mutex_lock() is no longer inadvertantly behaving as a cancelation point. - Thomas Pfaff <tpfaff@gmx.net> * pthread_mutex_timedlock() no longer occasionally sets incorrect mutex ownership, causing deadlocks in some applications. - Robert Strycek <strycek@posam.sk> and Alexander Terekhov <TEREKHOV@de.ibm.com> SNAPSHOT 2002-11-04 ------------------- Bug fixes --------- * sem_getvalue() now returns the correct value under Win NT and WinCE. - Rob Fanner <rfanner@stonethree.com> * sem_timedwait() now uses tighter checks for unreasonable abstime values - that would result in unexpected timeout values. * ptw32_cond_wait_cleanup() no longer mysteriously consumes CV signals but may produce more spurious wakeups. It is believed that the sem_timedwait() call is consuming a CV signal that it shouldn't. - Alexander Terekhov <TEREKHOV@de.ibm.com> * Fixed a memory leak in ptw32_threadDestroy() for implicit threads. * Fixed potential for deadlock in pthread_cond_destroy(). A deadlock could occur for statically declared CVs (PTHREAD_COND_INITIALIZER), when one thread is attempting to destroy the condition variable while another is attempting to dynamically initialize it. - Michael Johnson <michaelj@maine.rr.com> SNAPSHOT 2002-03-02 ------------------- Cleanup code default style. (IMPORTANT) ---------------------------------------------------------------------- Previously, if not defined, the cleanup style was determined automatically from the compiler/language, and one of the following was defined accordingly: __CLEANUP_SEH MSVC only __CLEANUP_CXX C++, including MSVC++, GNU G++ __CLEANUP_C C, including GNU GCC, not MSVC These defines determine the style of cleanup (see pthread.h) and, most importantly, the way that cancelation and thread exit (via pthread_exit) is performed (see the routine ptw32_throw() in private.c). In short, the exceptions versions of the library throw an exception when a thread is canceled or exits (via pthread_exit()), which is caught by a handler in the thread startup routine, so that the the correct stack unwinding occurs regardless of where the thread is when it's canceled or exits via pthread_exit(). In this and future snapshots, unless the build explicitly defines (e.g. via a compiler option) __CLEANUP_SEH, __CLEANUP_CXX, or __CLEANUP_C, then the build NOW always defaults to __CLEANUP_C style cleanup. This style uses setjmp/longjmp in the cancelation and pthread_exit implementations, and therefore won't do stack unwinding even when linked to applications that have it (e.g. C++ apps). This is for consistency with most current commercial Unix POSIX threads implementations. Compaq's TRU64 may be an exception (no pun intended) and possible future trend. Although it was not clearly documented before, it is still necessary to build your application using the same __CLEANUP_* define as was used for the version of the library that you link with, so that the correct parts of pthread.h are included. That is, the possible defines require the following library versions: __CLEANUP_SEH pthreadVSE.dll __CLEANUP_CXX pthreadVCE.dll or pthreadGCE.dll __CLEANUP_C pthreadVC.dll or pthreadGC.dll E.g. regardless of whether your app is C or C++, if you link with pthreadVC.lib or libpthreadGC.a, then you must define __CLEANUP_C. THE POINT OF ALL THIS IS: if you have not been defining one of these explicitly, then the defaults as described at the top of this section were being used. THIS NOW CHANGES, as has been explained above, but to try to make this clearer here's an example: If you were building your application with MSVC++ i.e. using C++ exceptions and not explicitly defining one of __CLEANUP_*, then __CLEANUP_C++ was automatically defined for you in pthread.h. You should have been linking with pthreadVCE.dll, which does stack unwinding. If you now build your application as you had before, pthread.h will now automatically set __CLEANUP_C as the default style, and you will need to link with pthreadVC.dll. Stack unwinding will now NOT occur when a thread is canceled, or the thread calls pthread_exit(). Your application will now most likely behave differently to previous versions, and in non-obvious ways. Most likely is that locally instantiated objects may not be destroyed or cleaned up after a thread is canceled. If you want the same behaviour as before, then you must now define __CLEANUP_C++ explicitly using a compiler option and link with pthreadVCE.dll as you did before. WHY ARE WE MAKING THE DEFAULT STYLE LESS EXCEPTION-FRIENDLY? Because no commercial Unix POSIX threads implementation allows you to choose to have stack unwinding. Therefore, providing it in pthread-win32 as a default is dangerous. We still provide the choice but unless you consciously choose to do otherwise, your pthreads applications will now run or crash in similar ways irrespective of the threads platform you use. Or at least this is the hope. WHY NOT REMOVE THE EXCEPTIONS VERSIONS OF THE LIBRARY ALTOGETHER? There are a few reasons: - because there are well respected POSIX threads people who believe that POSIX threads implementations should be exceptions aware and do the expected thing in that context. (There are equally respected people who believe it should not be easily accessible, if it's there at all, for unconditional conformity to other implementations.) - because pthreads-win32 is one of the few implementations that has the choice, perhaps the only freely available one, and so offers a laboratory to people who may want to explore the effects; - although the code will always be around somewhere for anyone who wants it, once it's removed from the current version it will not be nearly as visible to people who may have a use for it. Source module splitting ----------------------- In order to enable smaller image sizes to be generated for applications that link statically with the library, most routines have been separated out into individual source code files. This is being done in such a way as to be backward compatible. The old source files are reused to congregate the individual routine files into larger translation units (via a bunch of # includes) so that the compiler can still optimise wherever possible, e.g. through inlining, which can only be done within the same translation unit. It is also possible to build the entire library by compiling the single file named "pthread.c", which just #includes all the secondary congregation source files. The compiler may be able to use this to do more inlining of routines. Although the GNU compiler is able to produce libraries with the necessary separation (the -ffunction-segments switch), AFAIK, the MSVC and other compilers don't have this feature. Finally, since I use makefiles and command-line compilation, I don't know what havoc this reorganisation may wreak amongst IDE project file users. You should be able to continue using your existing project files without modification. New non-portable functions -------------------------- pthread_num_processors_np(): Returns the number of processors in the system that are available to the process, as determined from the processor affinity mask. pthread_timechange_handler_np(): To improve tolerance against operator or time service initiated system clock changes. This routine can be called by an application when it receives a WM_TIMECHANGE message from the system. At present it broadcasts all condition variables so that waiting threads can wake up and re-evaluate their conditions and restart their timed waits if required. - Suggested by Alexander Terekhov Platform dependence ------------------- As Win95 doesn't provide one, the library now contains it's own InterlockedCompareExchange() routine, which is used whenever Windows doesn't provide it. InterlockedCompareExchange() is used to implement spinlocks and barriers, and also in mutexes. This routine relies on the CMPXCHG machine instruction which is not available on i386 CPUs. This library (from snapshot 20010712 onwards) is therefore no longer supported on i386 processor platforms. New standard routines --------------------- For source code portability only - rwlocks cannot be process shared yet. pthread_rwlockattr_init() pthread_rwlockattr_destroy() pthread_rwlockattr_setpshared() pthread_rwlockattr_getpshared() As defined in the new POSIX standard, and the Single Unix Spec version 3: sem_timedwait() pthread_mutex_timedlock() - Alexander Terekhov and Thomas Pfaff pthread_rwlock_timedrdlock() - adapted from pthread_rwlock_rdlock() pthread_rwlock_timedwrlock() - adapted from pthread_rwlock_wrlock() pthread.h no longer includes windows.h -------------------------------------- [Not yet for G++] This was done to prevent conflicts. HANDLE, DWORD, and NULL are temporarily defined within pthread.h if they are not already. pthread.h, sched.h and semaphore.h now use dllexport/dllimport -------------------------------------------------------------- Not only to avoid the need for the pthread.def file, but to improve performance. Apparently, declaring functions with dllimport generates a direct call to the function and avoids the overhead of a stub function call. Bug fixes --------- * Fixed potential NULL pointer dereferences in pthread_mutexattr_init, pthread_mutexattr_getpshared, pthread_barrierattr_init, pthread_barrierattr_getpshared, and pthread_condattr_getpshared. - Scott McCaskill <scott@magruder.org> * Removed potential race condition in pthread_mutex_trylock and pthread_mutex_lock; - Alexander Terekhov <TEREKHOV@de.ibm.com> * The behaviour of pthread_mutex_trylock in relation to recursive mutexes was inconsistent with commercial implementations. Trylock would return EBUSY if the lock was owned already by the calling thread regardless of mutex type. Trylock now increments the recursion count and returns 0 for RECURSIVE mutexes, and will return EDEADLK rather than EBUSY for ERRORCHECK mutexes. This is consistent with Solaris. - Thomas Pfaff <tpfaff@gmx.net> * Found a fix for the library and workaround for applications for the known bug #2, i.e. where __CLEANUP_CXX or __CLEANUP_SEH is defined. See the "Known Bugs in this snapshot" section below. This could be made transparent to applications by replacing the macros that define the current C++ and SEH versions of pthread_cleanup_push/pop with the C version, but AFAIK cleanup handlers would not then run in the correct sequence with destructors and exception cleanup handlers when an exception occurs. * Cancelation once started in a thread cannot now be inadvertantly double canceled. That is, once a thread begins it's cancelation run, cancelation is disabled and a subsequent cancel request will return an error (ESRCH). * errno: An incorrect compiler directive caused a local version of errno to be used instead of the Win32 errno. Both instances are thread-safe but applications checking errno after a pthreads-win32 call would be wrong. Fixing this also fixed a bad compiler option in the testsuite (/MT should have been /MD) which is needed to link with the correct library MSVCRT.LIB. SNAPSHOT 2001-07-12 ------------------- To be added SNAPSHOT 2001-07-03 ------------------- To be added SNAPSHOT 2000-08-13 ------------------- New: - Renamed DLL and LIB files: pthreadVSE.dll (MS VC++/Structured EH) pthreadVSE.lib pthreadVCE.dll (MS VC++/C++ EH) pthreadVCE.lib pthreadGCE.dll (GNU G++/C++ EH) libpthreadw32.a Both your application and the pthread dll should use the same exception handling scheme. Bugs fixed: - MSVC++ C++ exception handling. Some new tests have been added. SNAPSHOT 2000-08-10 ------------------- New: - asynchronous cancelation on X86 (Jason Nye) - Makefile compatible with MS nmake to replace buildlib.bat - GNUmakefile for Mingw32 - tests/Makefile for MS nmake replaces runall.bat - tests/GNUmakefile for Mingw32 Bugs fixed: - kernel32 load/free problem - attempt to hide internel exceptions from application exception handlers (__try/__except and try/catch blocks) - Win32 thread handle leakage bug (David Baggett/Paul Redondo/Eyal Lebedinsky) Some new tests have been added. SNAPSHOT 1999-11-02 ------------------- Bugs fixed: - ctime_r macro had an incorrect argument (Erik Hensema), - threads were not being created PTHREAD_CANCEL_DEFERRED. This should have had little effect as deferred is the only supported type. (Ross Johnson). Some compatibility improvements added, eg. - pthread_setcancelstate accepts NULL pointer for the previous value argument. Ditto for pthread_setcanceltype. This is compatible with Solaris but should not affect standard applications (Erik Hensema) Some new tests have been added. SNAPSHOT 1999-10-17 ------------------- Bug fix - Cancelation of threads waiting on condition variables now works properly (Lorin Hochstein and Peter Slacik) SNAPSHOT 1999-08-12 ------------------- Fixed exception stack cleanup if calling pthread_exit() - (Lorin Hochstein and John Bossom). Fixed bugs in condition variables - (Peter Slacik): - additional contention checks - properly adjust number of waiting threads after timed condvar timeout. SNAPSHOT 1999-05-30 ------------------- Some minor bugs have been fixed. See the ChangeLog file for details. Some more POSIX 1b functions are now included but ony return an error (ENOSYS) if called. They are: sem_open sem_close sem_unlink sem_getvalue SNAPSHOT 1999-04-07 ------------------- Some POSIX 1b functions which were internally supported are now available as exported functions: sem_init sem_destroy sem_wait sem_trywait sem_post sched_yield sched_get_priority_min sched_get_priority_max Some minor bugs have been fixed. See the ChangeLog file for details. SNAPSHOT 1999-03-16 ------------------- Initial release.