svn merge ^/branches/released .

1 files changed, 451 insertions, 403 deletions

diff --git a/pthreads/FAQ b/pthreads/FAQ
index 4f2d449b9..d7399c3ef 100644
--- a/pthreads/FAQ
+++ b/pthreads/FAQ
@@ -1,403 +1,451 @@
-		  =========================================
-		  PTHREADS-WIN32 Frequently Asked Questions
-		  =========================================
-
-INDEX
------
-
-Q 1	What is it?
-
-Q 2	Which of the several dll versions do I use?
-	or,
-	What are all these pthread*.dll and pthread*.lib files?
-
-Q 3	What is the library naming convention?
-
-Q 4	Cleanup code default style or: it used to work when I built
-	the library myself, but now it doesn't - why?
-
-Q 5	Why is the default library version now less exception-friendly?
-
-Q 6	Should I use Cygwin or Mingw32 as a development environment?
-
-Q 7	Now that pthreads-win32 builds under Mingw32, why do I get
-	memory access violations (segfaults)?
-
-Q 8	How do I use pthread.dll for Win32 (Visual C++ 5.0)
-
-Q 9	Cancelation doesn't work for me, why?
-
-Q 10	How do I generate pthreadGCE.dll and libpthreadw32.a for use
-	with Mingw32?
-
-=============================================================================
-
-Q 1	What is it?
----
-
-Pthreads-win32 is an Open Source Software 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. The library also supports
-some of the functionality of the Open Group's Single Unix
-specification, version 2, namely mutex types.
-
-See the file "ANNOUNCE" for more information including standards
-conformance details and list of supported routines.
-
-
-------------------------------------------------------------------------------
-
-Q 2	Which of the several dll versions do I use?
----	or,
-	What are all these pthread*.dll and pthread*.lib files?
-
-Simply, you only use one of them, but you need to choose carefully.
-
-The most important choice you need to make is whether to use a
-version that uses exceptions internally, or not (there are versions
-of the library that use exceptions as part of the thread
-cancelation and cleanup implementation, and one that uses
-setjmp/longjmp instead).
-
-There is some contension amongst POSIX threads experts as
-to how POSIX threads cancelation and exit should work
-with languages that include exceptions and handlers, e.g.
-C++ and even C (Microsoft's Structured Exceptions).
-
-The issue is: should cancelation of a thread in, say,
-a C++ application cause object destructors and C++ exception
-handlers to be invoked as the stack unwinds during thread
-exit, or not?
-
-There seems to be more opinion in favour of using the
-standard C version of the library (no EH) with C++ applications
-since this appears to be the assumption commercial pthreads
-implementations make. Therefore, if you use an EH version
-of pthreads-win32 then you may be under the illusion that
-your application will be portable, when in fact it is likely to
-behave very differently linked with other pthreads libraries.
-
-Now you may be asking: why have you kept the EH versions of
-the library?
-
-There are a couple of reasons:
-- there is division amongst the experts and so the code may
-  be needed in the future. (Yes, it's in the repository and we
-  can get it out anytime in the future, but ...)
-- pthreads-win32 is one of the few implementations, and possibly
-  the only freely available one, that has EH versions. It may be
-  useful to people who want to play with or study application
-  behaviour under these conditions.
-
-
-------------------------------------------------------------------------------
-
-Q 3	What is the library naming convention?
----
-
-Because the library is being built using various exception
-handling schemes and compilers - and because the library
-may not work reliably if these are mixed in an application,
-each different version of the library has it's own name.
-
-Note 1: the incompatibility is really between EH implementations
-of the different compilers. It should be possible to use the
-standard C version from either compiler with C++ applications
-built with a different compiler. If you use an EH version of
-the library, then you must use the same compiler for the
-application. This is another complication and dependency that
-can be avoided by using only the standard C library version.
-
-Note 2: if you use a standard C pthread*.dll with a C++
-application, then any functions that you define that are
-intended to be called via pthread_cleanup_push() must be
-__cdecl.
-
-Note 3: the intention is to also name either the VC or GC
-version (it should be arbitrary) as pthread.dll, including
-pthread.lib and libpthread.a as appropriate.
-
-In general:
-	pthread[VG]{SE,CE,C}.dll
-	pthread[VG]{SE,CE,C}.lib
-
-where:
-	[VG] indicates the compiler
-	V	- MS VC
-	G	- GNU C
-
-	{SE,CE,C} indicates the exception handling scheme
-	SE	- Structured EH
-	CE	- C++ EH
-	C	- no exceptions - uses setjmp/longjmp
-
-For example:
-	pthreadVSE.dll	(MSVC/SEH)
-	pthreadGCE.dll	(GNUC/C++ EH)
-	pthreadGC.dll	(GNUC/not dependent on exceptions)
-
-The GNU library archive file names have changed to:
-
-	libpthreadGCE.a
-	libpthreadGC.a
-
-
-------------------------------------------------------------------------------
-
-Q 4	Cleanup code default style or: it used to work when I built
----	the library myself, but now it doesn't - why?
-
-Up to and including snapshot 2001-07-12, if not defined, the cleanup
-style was determined automatically from the compiler used, 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().
-
-After snapshot 2001-07-12, unless your 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/all
-commercial Unix POSIX threads implementations.
-
-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
-
-THE POINT OF ALL THIS IS: if you have not been defining one of these
-explicitly, then the defaults have been set according to the compiler
-and language you are using, as described at the top of this
-section.
-
-THIS NOW CHANGES, as has been explained above. For example:
-
-If you were building your application with MSVC++ i.e. using C++
-exceptions (rather than SEH) and not explicitly defining one of
-__CLEANUP_*, then __CLEANUP_C++ was 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
-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, nor when 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 local
-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.
-
-
-------------------------------------------------------------------------------
-
-Q 5	Why is the default library version now less exception-friendly?
----
-
-Because most commercial Unix POSIX threads implementations don't allow you to
-choose to have stack unwinding. (Compaq's TRU64 Unix is possibly an exception.)
-
-Therefore, providing it in pthread-win32 as a default could be dangerous
-and non-portable. We still provide the choice but you must now consciously
-make it.
-
-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.)
-- 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.
-
-
-------------------------------------------------------------------------------
-
-Q 6	Should I use Cygwin or Mingw32 as a development environment?
----
-
-Important: see Q7 also.
-
-Use Mingw32 with the MSVCRT library to build applications that use
-the pthreads DLL.
-
-Cygwin's own internal support for POSIX threads is growing.
-Consult that project's documentation for more information.
-
-------------------------------------------------------------------------------
-
-Q 7	Now that pthreads-win32 builds under Mingw32, why do I get
----	memory access violations (segfaults)?
-
-The latest Mingw32 package has thread-safe exception handling (see Q10).
-Also, see Q6 above.
-
-------------------------------------------------------------------------------
-
-Q 8	How do I use pthread.dll for Win32 (Visual C++ 5.0)
----	
-
->
-> I'm a "rookie" when it comes to your pthread implementation.	I'm currently
-> desperately trying to install the prebuilt .dll file into my MSVC compiler.
-> Could you please provide me with explicit instructions on how to do this (or
-> direct me to a resource(s) where I can acquire such information)?
->
-> Thank you,
->
-
-You should have a .dll, .lib, .def, and three .h files. It is recommended
-that you use pthreadVC.dll, rather than pthreadVCE.dll or pthreadVSE.dll
-(see Q2 above).
-
-The .dll can go in any directory listed in your PATH environment
-variable, so putting it into C:\WINDOWS should work.
-
-The .lib file can go in any directory listed in your LIB environment
-variable.
-
-The .h files can go in any directory listed in your INCLUDE
-environment variable.
-
-Or you might prefer to put the .lib and .h files into a new directory
-and add its path to LIB and INCLUDE. You can probably do this easiest
-by editing the file:-
-
-C:\Program Files\DevStudio\vc\bin\vcvars32.bat
-
-The .def file isn't used by anything in the pre-compiled version but 
-is included for information.
-
-Cheers.
-Ross
-
-------------------------------------------------------------------------------
-
-Q 9	Cancelation doesn't work for me, why?
----
-
-> I'm investigating a problem regarding thread cancelation. The thread I want
-> to cancel has PTHREAD_CANCEL_ASYNCHRONOUS, however, this piece of code
-> blocks on the join():
->
->		if ((retv = Pthread_cancel( recvThread )) == 0)
->		{
->			retv = Pthread_join( recvThread, 0 );
->		}
->
-> Pthread_* are just macro's; they call pthread_*.
->
-> The thread recvThread seems to block on a select() call. It doesn't get
-> cancelled.
->
-> Two questions:
->
-> 1) is this normal behaviour?
->
-> 2) if not, how does the cancel mechanism work? I'm not very familliar to
-> win32 programming, so I don't really understand how the *Event() family of
-> calls work.
-
-The answer to your first question is, normal POSIX behaviour would  
-be to asynchronously cancel the thread. However, even that doesn't
-guarantee cancelation as the standard only says it should be
-cancelled as soon as possible.
-
-Snapshot 99-11-02 or earlier only partially supports asynchronous cancellation.
-Snapshots since then simulate async cancelation by poking the address of
-a cancelation routine into the PC of the threads context. This requires
-the thread to be resumed in some way for the cancelation to actually
-proceed. This is not true async cancelation, but it is as close as we've
-been able to get to it.
-
-If the thread you're trying to cancel is blocked (for instance, it could be
-waiting for data from the network), it will only get cancelled when it unblocks
-(when the data arrives). For true pre-emptive cancelation in these cases,
-pthreads-win32 from snapshot 2004-05-16 can automatically recognise and use the
-QueueUserAPCEx package by Panagiotis E. Hadjidoukas. This package is available
-from the pthreads-win32 ftp site and is included in the pthreads-win32
-self-unpacking zip from 2004-05-16 onwards.
-
-Using deferred cancelation would normally be the way to go, however,
-even though the POSIX threads standard lists a number of C library
-functions that are defined as deferred cancelation points, there is
-no hookup between those which are provided by Windows and the
-pthreads-win32 library.
-
-Incidently, it's worth noting for code portability that the older POSIX
-threads standards cancelation point lists didn't include "select" because
-(as I read in Butenhof) it wasn't part of POSIX. However, it does appear in
-the SUSV3.
-
-Effectively, the only mandatory cancelation points that pthreads-win32
-recognises are those the library implements itself, ie.
-	
-	pthread_testcancel
-	pthread_cond_wait
-	pthread_cond_timedwait
-	pthread_join
-	sem_wait
-	sem_timedwait
-	pthread_delay_np
-
-The following routines from the non-mandatory list in SUSV3 are
-cancelation points in pthreads-win32:
-
-	pthread_rwlock_wrlock
-	pthread_rwlock_timedwrlock
-
-The following routines from the non-mandatory list in SUSV3 are not
-cancelation points in pthreads-win32:
-
-	pthread_rwlock_rdlock
-	pthread_rwlock_timedrdlock
-
-Pthreads-win32 also provides two functions that allow you to create
-cancelation points within your application, but only for cases where
-a thread is going to block on a Win32 handle. These are:
-
-	pthreadCancelableWait(HANDLE waitHandle) /* Infinite wait */
- 
-	pthreadCancelableTimedWait(HANDLE waitHandle, DWORD timeout)
-
-------------------------------------------------------------------------------
- 
-
-Q 10	How do I create thread-safe applications using
-----	pthreadGCE.dll, libpthreadw32.a and Mingw32?
-
-This should not be a problem with recent versions of MinGW32.
-
-For early versions, see Thomas Pfaff's email at:
-http://sources.redhat.com/ml/pthreads-win32/2002/msg00000.html
-------------------------------------------------------------------------------
- 
+		  =========================================

+		  PTHREADS-WIN32 Frequently Asked Questions

+		  =========================================

+

+INDEX

+-----

+

+Q 1	What is it?

+

+Q 2	Which of the several dll versions do I use?

+	or,

+	What are all these pthread*.dll and pthread*.lib files?

+

+Q 3	What is the library naming convention?

+

+Q 4	Cleanup code default style or: it used to work when I built

+	the library myself, but now it doesn't - why?

+

+Q 5	Why is the default library version now less exception-friendly?

+

+Q 6	Should I use Cygwin or Mingw32 as a development environment?

+

+Q 7	Now that pthreads-win32 builds under Mingw32, why do I get

+	memory access violations (segfaults)?

+

+Q 8	How do I use pthread.dll for Win32 (Visual C++ 5.0)

+

+Q 9	Cancelation doesn't work for me, why?

+

+Q 10	How do I generate pthreadGCE.dll and libpthreadw32.a for use

+	with Mingw32?

+

+Q 11    Why isn't pthread_t defined as a scalar (e.g. pointer or int)

+        like it is for other POSIX threads implementations?

+

+=============================================================================

+

+Q 1	What is it?

+---

+

+Pthreads-win32 is an Open Source Software 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. The library also supports

+some of the functionality of the Open Group's Single Unix

+specification, version 2, namely mutex types.

+

+See the file "ANNOUNCE" for more information including standards

+conformance details and list of supported routines.

+

+

+------------------------------------------------------------------------------

+

+Q 2	Which of the several dll versions do I use?

+---	or,

+	What are all these pthread*.dll and pthread*.lib files?

+

+Simply, you only use one of them, but you need to choose carefully.

+

+The most important choice you need to make is whether to use a

+version that uses exceptions internally, or not (there are versions

+of the library that use exceptions as part of the thread

+cancelation and cleanup implementation, and one that uses

+setjmp/longjmp instead).

+

+There is some contension amongst POSIX threads experts as

+to how POSIX threads cancelation and exit should work

+with languages that include exceptions and handlers, e.g.

+C++ and even C (Microsoft's Structured Exceptions).

+

+The issue is: should cancelation of a thread in, say,

+a C++ application cause object destructors and C++ exception

+handlers to be invoked as the stack unwinds during thread

+exit, or not?

+

+There seems to be more opinion in favour of using the

+standard C version of the library (no EH) with C++ applications

+since this appears to be the assumption commercial pthreads

+implementations make. Therefore, if you use an EH version

+of pthreads-win32 then you may be under the illusion that

+your application will be portable, when in fact it is likely to

+behave very differently linked with other pthreads libraries.

+

+Now you may be asking: why have you kept the EH versions of

+the library?

+

+There are a couple of reasons:

+- there is division amongst the experts and so the code may

+  be needed in the future. (Yes, it's in the repository and we

+  can get it out anytime in the future, but ...)

+- pthreads-win32 is one of the few implementations, and possibly

+  the only freely available one, that has EH versions. It may be

+  useful to people who want to play with or study application

+  behaviour under these conditions.

+

+

+------------------------------------------------------------------------------

+

+Q 3	What is the library naming convention?

+---

+

+Because the library is being built using various exception

+handling schemes and compilers - and because the library

+may not work reliably if these are mixed in an application,

+each different version of the library has it's own name.

+

+Note 1: the incompatibility is really between EH implementations

+of the different compilers. It should be possible to use the

+standard C version from either compiler with C++ applications

+built with a different compiler. If you use an EH version of

+the library, then you must use the same compiler for the

+application. This is another complication and dependency that

+can be avoided by using only the standard C library version.

+

+Note 2: if you use a standard C pthread*.dll with a C++

+application, then any functions that you define that are

+intended to be called via pthread_cleanup_push() must be

+__cdecl.

+

+Note 3: the intention is to also name either the VC or GC

+version (it should be arbitrary) as pthread.dll, including

+pthread.lib and libpthread.a as appropriate.

+

+In general:

+	pthread[VG]{SE,CE,C}.dll

+	pthread[VG]{SE,CE,C}.lib

+

+where:

+	[VG] indicates the compiler

+	V	- MS VC

+	G	- GNU C

+

+	{SE,CE,C} indicates the exception handling scheme

+	SE	- Structured EH

+	CE	- C++ EH

+	C	- no exceptions - uses setjmp/longjmp

+

+For example:

+	pthreadVSE.dll	(MSVC/SEH)

+	pthreadGCE.dll	(GNUC/C++ EH)

+	pthreadGC.dll	(GNUC/not dependent on exceptions)

+

+The GNU library archive file names have changed to:

+

+	libpthreadGCE.a

+	libpthreadGC.a

+

+

+------------------------------------------------------------------------------

+

+Q 4	Cleanup code default style or: it used to work when I built

+---	the library myself, but now it doesn't - why?

+

+Up to and including snapshot 2001-07-12, if not defined, the cleanup

+style was determined automatically from the compiler used, 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().

+

+After snapshot 2001-07-12, unless your 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/all

+commercial Unix POSIX threads implementations.

+

+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

+

+THE POINT OF ALL THIS IS: if you have not been defining one of these

+explicitly, then the defaults have been set according to the compiler

+and language you are using, as described at the top of this

+section.

+

+THIS NOW CHANGES, as has been explained above. For example:

+

+If you were building your application with MSVC++ i.e. using C++

+exceptions (rather than SEH) and not explicitly defining one of

+__CLEANUP_*, then __CLEANUP_C++ was 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

+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, nor when 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 local

+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.

+

+

+------------------------------------------------------------------------------

+

+Q 5	Why is the default library version now less exception-friendly?

+---

+

+Because most commercial Unix POSIX threads implementations don't allow you to

+choose to have stack unwinding. (Compaq's TRU64 Unix is possibly an exception.)

+

+Therefore, providing it in pthread-win32 as a default could be dangerous

+and non-portable. We still provide the choice but you must now consciously

+make it.

+

+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.)

+- 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.

+

+

+------------------------------------------------------------------------------

+

+Q 6	Should I use Cygwin or Mingw32 as a development environment?

+---

+

+Important: see Q7 also.

+

+Use Mingw32 with the MSVCRT library to build applications that use

+the pthreads DLL.

+

+Cygwin's own internal support for POSIX threads is growing.

+Consult that project's documentation for more information.

+

+------------------------------------------------------------------------------

+

+Q 7	Now that pthreads-win32 builds under Mingw32, why do I get

+---	memory access violations (segfaults)?

+

+The latest Mingw32 package has thread-safe exception handling (see Q10).

+Also, see Q6 above.

+

+------------------------------------------------------------------------------

+

+Q 8	How do I use pthread.dll for Win32 (Visual C++ 5.0)

+---	

+

+>

+> I'm a "rookie" when it comes to your pthread implementation.	I'm currently

+> desperately trying to install the prebuilt .dll file into my MSVC compiler.

+> Could you please provide me with explicit instructions on how to do this (or

+> direct me to a resource(s) where I can acquire such information)?

+>

+> Thank you,

+>

+

+You should have a .dll, .lib, .def, and three .h files. It is recommended

+that you use pthreadVC.dll, rather than pthreadVCE.dll or pthreadVSE.dll

+(see Q2 above).

+

+The .dll can go in any directory listed in your PATH environment

+variable, so putting it into C:\WINDOWS should work.

+

+The .lib file can go in any directory listed in your LIB environment

+variable.

+

+The .h files can go in any directory listed in your INCLUDE

+environment variable.

+

+Or you might prefer to put the .lib and .h files into a new directory

+and add its path to LIB and INCLUDE. You can probably do this easiest

+by editing the file:-

+

+C:\Program Files\DevStudio\vc\bin\vcvars32.bat

+

+The .def file isn't used by anything in the pre-compiled version but 

+is included for information.

+

+Cheers.

+Ross

+

+------------------------------------------------------------------------------

+

+Q 9	Cancelation doesn't work for me, why?

+---

+

+> I'm investigating a problem regarding thread cancelation. The thread I want

+> to cancel has PTHREAD_CANCEL_ASYNCHRONOUS, however, this piece of code

+> blocks on the join():

+>

+>		if ((retv = Pthread_cancel( recvThread )) == 0)

+>		{

+>			retv = Pthread_join( recvThread, 0 );

+>		}

+>

+> Pthread_* are just macro's; they call pthread_*.

+>

+> The thread recvThread seems to block on a select() call. It doesn't get

+> cancelled.

+>

+> Two questions:

+>

+> 1) is this normal behaviour?

+>

+> 2) if not, how does the cancel mechanism work? I'm not very familliar to

+> win32 programming, so I don't really understand how the *Event() family of

+> calls work.

+

+The answer to your first question is, normal POSIX behaviour would  

+be to asynchronously cancel the thread. However, even that doesn't

+guarantee cancelation as the standard only says it should be

+cancelled as soon as possible.

+

+Snapshot 99-11-02 or earlier only partially supports asynchronous cancellation.

+Snapshots since then simulate async cancelation by poking the address of

+a cancelation routine into the PC of the threads context. This requires

+the thread to be resumed in some way for the cancelation to actually

+proceed. This is not true async cancelation, but it is as close as we've

+been able to get to it.

+

+If the thread you're trying to cancel is blocked (for instance, it could be

+waiting for data from the network), it will only get cancelled when it unblocks

+(when the data arrives). For true pre-emptive cancelation in these cases,

+pthreads-win32 from snapshot 2004-05-16 can automatically recognise and use the

+QueueUserAPCEx package by Panagiotis E. Hadjidoukas. This package is available

+from the pthreads-win32 ftp site and is included in the pthreads-win32

+self-unpacking zip from 2004-05-16 onwards.

+

+Using deferred cancelation would normally be the way to go, however,

+even though the POSIX threads standard lists a number of C library

+functions that are defined as deferred cancelation points, there is

+no hookup between those which are provided by Windows and the

+pthreads-win32 library.

+

+Incidently, it's worth noting for code portability that the older POSIX

+threads standards cancelation point lists didn't include "select" because

+(as I read in Butenhof) it wasn't part of POSIX. However, it does appear in

+the SUSV3.

+

+Effectively, the only mandatory cancelation points that pthreads-win32

+recognises are those the library implements itself, ie.

+	

+	pthread_testcancel

+	pthread_cond_wait

+	pthread_cond_timedwait

+	pthread_join

+	sem_wait

+	sem_timedwait

+	pthread_delay_np

+

+The following routines from the non-mandatory list in SUSV3 are

+cancelation points in pthreads-win32:

+

+	pthread_rwlock_wrlock

+	pthread_rwlock_timedwrlock

+

+The following routines from the non-mandatory list in SUSV3 are not

+cancelation points in pthreads-win32:

+

+	pthread_rwlock_rdlock

+	pthread_rwlock_timedrdlock

+

+Pthreads-win32 also provides two functions that allow you to create

+cancelation points within your application, but only for cases where

+a thread is going to block on a Win32 handle. These are:

+

+	pthreadCancelableWait(HANDLE waitHandle) /* Infinite wait */

+ 

+	pthreadCancelableTimedWait(HANDLE waitHandle, DWORD timeout)

+

+------------------------------------------------------------------------------

+ 

+

+Q 10	How do I create thread-safe applications using

+----	pthreadGCE.dll, libpthreadw32.a and Mingw32?

+

+This should not be a problem with recent versions of MinGW32.

+

+For early versions, see Thomas Pfaff's email at:

+http://sources.redhat.com/ml/pthreads-win32/2002/msg00000.html

+------------------------------------------------------------------------------

+

+Q 11    Why isn't pthread_t defined as a scalar (e.g. pointer or int)

+        like it is for other POSIX threads implementations?

+----

+

+Originally pthread_t was defined as a pointer (to the opaque pthread_t_

+struct) and later it was changed to a struct containing the original

+pointer plus a sequence counter. This is allowed under both the original

+POSIX Threads Standard and the current Single Unix Specification.

+

+When pthread_t is a simple pointer to a struct some very difficult to

+debug problems arise from the process of freeing and later allocing

+thread structs because new pthread_t handles can acquire the identity of

+previously detached threads. The change to a struct was made, along with

+some changes to their internal managment, in order to guarantee (for

+practical applications) that the pthread_t handle will be unique over the

+life of the running process.

+

+Where application code attempts to compare one pthread_t against another

+directly, a compiler error will be emitted because structs can't be

+compared at that level. This should signal a potentially serious problem

+in the code design, which would go undetected if pthread_t was a scalar.

+

+The POSIX Threading API provides a function named pthread_equal() to

+compare pthread_t thread handles.

+

+Other pthreads implementations, such as Sun's, use an int as the handle

+but do guarantee uniqueness within the process scope. Win32 scalar typed

+thread handles also guarantee uniqueness in system scope. It wasn't clear

+how well the internal management of these handles would scale as the

+number of threads and the fragmentation of the sequence numbering

+increased for applications where thousands or millions of threads are

+created and detached over time. The current management of threads within

+pthreads-win32 using structs for pthread_t, and reusing without ever

+freeing them, reduces the management time overheads to a constant, which

+could be important given that pthreads-win32 threads are built on top of

+Win32 threads and will therefore include that management overhead on top

+of their own. The cost is that the memory resources used for thread

+handles will remain at the peak level until the process exits.

+

+While it may be inconvenient for developers to be forced away from making

+assumptions about the internals of pthread_t, the advantage for the

+future development of pthread-win32, as well as those applications that

+use it and other pthread implementations, is that the library is free to

+change pthread_t internals and management as better methods arise.

+