This file documents non-portable functions and other issues.

Non-portable functions included in pthreads-win32
-------------------------------------------------

BOOL
pthread_win32_test_features_np(int mask)

	This routine allows an application to check which
	run-time auto-detected features are available within
	the library.

	The possible features are:

		PTW32_SYSTEM_INTERLOCKED_COMPARE_EXCHANGE
			Return TRUE if the native version of
			InterlockedCompareExchange() is being used.
		PTW32_ALERTABLE_ASYNC_CANCEL
			Return TRUE is the QueueUserAPCEx package
			QUSEREX.DLL is available and the AlertDrv.sys
			driver is loaded into Windows, providing
			alertable (pre-emptive) asyncronous threads
			cancelation. If this feature returns FALSE
			then the default async cancel scheme is in
			use, which cannot cancel blocked threads.

	Features may be Or'ed into the mask parameter, in which case
	the routine returns TRUE if any of the Or'ed features would
	return TRUE. At this stage it doesn't make sense to Or features
	but it may some day.


void *
pthread_timechange_handler_np(void *)

        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.

        It has the same return type and argument type as a
        thread routine so that it may be called directly
        through pthread_create(), i.e. as a separate thread.

        Parameters

        Although a parameter must be supplied, it is ignored.
        The value NULL can be used.

        Return values

        It can return an error EAGAIN to indicate that not
        all condition variables were broadcast for some reason.
        Otherwise, 0 is returned.

        If run as a thread, the return value is returned
        through pthread_join().

        The return value should be cast to an integer.


HANDLE
pthread_getw32threadhandle_np(pthread_t thread);

	Returns the win32 thread handle that the POSIX
	thread "thread" is running as.

	Applications can use the win32 handle to set
	win32 specific attributes of the thread.


int
pthread_mutexattr_setkind_np(pthread_mutexattr_t * attr, int kind)

int
pthread_mutexattr_getkind_np(pthread_mutexattr_t * attr, int *kind)

        These two routines are included for Linux compatibility
        and are direct equivalents to the standard routines
                pthread_mutexattr_settype
                pthread_mutexattr_gettype

        pthread_mutexattr_setkind_np accepts the following
        mutex kinds:
                PTHREAD_MUTEX_FAST_NP
                PTHREAD_MUTEX_ERRORCHECK_NP
                PTHREAD_MUTEX_RECURSIVE_NP

        These are really just equivalent to (respectively):
                PTHREAD_MUTEX_NORMAL
                PTHREAD_MUTEX_ERRORCHECK
                PTHREAD_MUTEX_RECURSIVE

int
pthread_delay_np (const struct timespec *interval);

        This routine causes a thread to delay execution for a specific period of time.
        This period ends at the current time plus the specified interval. The routine
        will not return before the end of the period is reached, but may return an
        arbitrary amount of time after the period has gone by. This can be due to
        system load, thread priorities, and system timer granularity.

        Specifying an interval of zero (0) seconds and zero (0) nanoseconds is
        allowed and can be used to force the thread to give up the processor or to
        deliver a pending cancelation request.

        This routine is a cancelation point.

        The timespec structure contains the following two fields:

                tv_sec is an integer number of seconds.
                tv_nsec is an integer number of nanoseconds. 

        Return Values

        If an error condition occurs, this routine returns an integer value
        indicating the type of error. Possible return values are as follows:

        0          Successful completion. 
        [EINVAL]   The value specified by interval is invalid. 

int
pthread_num_processors_np

        This routine (found on HPUX systems) returns the number of processors
        in the system. This implementation actually returns the number of
        processors available to the process, which can be a lower number
        than the system's number, depending on the process's affinity mask.

BOOL
pthread_win32_process_attach_np (void);

BOOL
pthread_win32_process_detach_np (void);

BOOL
pthread_win32_thread_attach_np (void);

BOOL
pthread_win32_thread_detach_np (void);

	These functions contain the code normally run via dllMain
	when the library is used as a dll but which need to be
	called explicitly by an application when the library
	is statically linked.

	You will need to call pthread_win32_process_attach_np() before
	you can call any pthread routines when statically linking.
	You should call pthread_win32_process_detach_np() before
	exiting your application to clean up.

	pthread_win32_thread_attach_np() is currently a no-op, but
	pthread_win32_thread_detach_np() is needed to clean up
	the implicit pthread handle that is allocated to a Win32 thread if
	it calls certain pthreads routines. Call this routine when the
	Win32 thread exits.

	These functions invariably return TRUE except for
	pthread_win32_process_attach_np() which will return FALSE
	if pthreads-win32 initialisation fails.

int
pthreadCancelableWait (HANDLE waitHandle);

int
pthreadCancelableTimedWait (HANDLE waitHandle, DWORD timeout);

	These two functions provide hooks into the pthread_cancel
	mechanism that will allow you to wait on a Windows handle
	and make it a cancellation point. Both functions block
	until either the given w32 handle is signaled, or
	pthread_cancel has been called. It is implemented using
	WaitForMultipleObjects on 'waitHandle' and a manually
	reset w32 event used to implement pthread_cancel.


Non-portable issues
-------------------

Thread priority

	POSIX defines a single contiguous range of numbers that determine a
	thread's priority. Win32 defines priority classes and priority
	levels relative to these classes. Classes are simply priority base
	levels that the defined priority levels are relative to such that,
	changing a process's priority class will change the priority of all
	of it's threads, while the threads retain the same relativity to each
	other.

	A Win32 system defines a single contiguous monotonic range of values
	that define system priority levels, just like POSIX. However, Win32
	restricts individual threads to a subset of this range on a
	per-process basis.

	The following table shows the base priority levels for combinations
	of priority class and priority value in Win32.
	
	 Process Priority Class               Thread Priority Level
	 -----------------------------------------------------------------
	 1 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_IDLE
	 1 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_IDLE
	 1 NORMAL_PRIORITY_CLASS              THREAD_PRIORITY_IDLE
	 1 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_IDLE
	 1 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_IDLE
	 2 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_LOWEST
	 3 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_BELOW_NORMAL
	 4 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_NORMAL
	 4 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_LOWEST
	 5 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_ABOVE_NORMAL
	 5 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_BELOW_NORMAL
	 5 Background NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_LOWEST
	 6 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_HIGHEST
	 6 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_NORMAL
	 6 Background NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_BELOW_NORMAL
	 7 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_ABOVE_NORMAL
	 7 Background NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_NORMAL
	 7 Foreground NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_LOWEST
 	 8 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_HIGHEST
	 8 NORMAL_PRIORITY_CLASS              THREAD_PRIORITY_ABOVE_NORMAL
	 8 Foreground NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_BELOW_NORMAL
	 8 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_LOWEST
	 9 NORMAL_PRIORITY_CLASS              THREAD_PRIORITY_HIGHEST
	 9 Foreground NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_NORMAL
	 9 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_BELOW_NORMAL
	10 Foreground NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_ABOVE_NORMAL
	10 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_NORMAL
	11 Foreground NORMAL_PRIORITY_CLASS   THREAD_PRIORITY_HIGHEST
	11 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_ABOVE_NORMAL
	11 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_LOWEST
	12 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_HIGHEST
	12 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_BELOW_NORMAL
	13 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_NORMAL
	14 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_ABOVE_NORMAL
	15 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_HIGHEST
	15 HIGH_PRIORITY_CLASS                THREAD_PRIORITY_TIME_CRITICAL
	15 IDLE_PRIORITY_CLASS                THREAD_PRIORITY_TIME_CRITICAL
	15 BELOW_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_TIME_CRITICAL
	15 NORMAL_PRIORITY_CLASS              THREAD_PRIORITY_TIME_CRITICAL
	15 ABOVE_NORMAL_PRIORITY_CLASS        THREAD_PRIORITY_TIME_CRITICAL
	16 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_IDLE
	17 REALTIME_PRIORITY_CLASS            -7
	18 REALTIME_PRIORITY_CLASS            -6
	19 REALTIME_PRIORITY_CLASS            -5
	20 REALTIME_PRIORITY_CLASS            -4
	21 REALTIME_PRIORITY_CLASS            -3
	22 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_LOWEST
	23 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_BELOW_NORMAL
	24 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_NORMAL
	25 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_ABOVE_NORMAL
	26 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_HIGHEST
	27 REALTIME_PRIORITY_CLASS             3
	28 REALTIME_PRIORITY_CLASS             4
	29 REALTIME_PRIORITY_CLASS             5
	30 REALTIME_PRIORITY_CLASS             6
	31 REALTIME_PRIORITY_CLASS            THREAD_PRIORITY_TIME_CRITICAL
	
	Windows NT:  Values -7, -6, -5, -4, -3, 3, 4, 5, and 6 are not supported.


	As you can see, the real priority levels available to any individual
	Win32 thread are non-contiguous.

	An application using pthreads-win32 should not make assumptions about
	the numbers used to represent thread priority levels, except that they
	are monotonic between the values returned by sched_get_priority_min()
	and sched_get_priority_max(). E.g. Windows 95, 98, NT, 2000, XP make
	available a non-contiguous range of numbers between -15 and 15, while
	at least one version of WinCE (3.0) defines the minimum priority
	(THREAD_PRIORITY_LOWEST) as 5, and the maximum priority
	(THREAD_PRIORITY_HIGHEST) as 1.

	Internally, pthreads-win32 maps any priority levels between
	THREAD_PRIORITY_IDLE and THREAD_PRIORITY_LOWEST to THREAD_PRIORITY_LOWEST,
	or between THREAD_PRIORITY_TIME_CRITICAL and THREAD_PRIORITY_HIGHEST to
	THREAD_PRIORITY_HIGHEST. Currently, this also applies to
	REALTIME_PRIORITY_CLASSi even if levels -7, -6, -5, -4, -3, 3, 4, 5, and 6
	are supported.

	If it wishes, a Win32 application using pthreads-win32 can use the Win32
	defined priority macros THREAD_PRIORITY_IDLE through
	THREAD_PRIORITY_TIME_CRITICAL.