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Diffstat (limited to 'FAQ')
| -rw-r--r-- | FAQ | 785 |
1 files changed, 392 insertions, 393 deletions
@@ -1,393 +1,392 @@ - ========================================= - 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 Thread won't block after two calls to mutex_lock - -Q 11 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 exit 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. 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. - -Async cancelation should be in versions post snapshot-1999-11-02 -of pthreads-win32 (currently only for x86 architectures). - -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. - -However ... - -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). Unfortunately, there is no way to do so from -outside the thread. - -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 POSIX -threads standard list doesn't include "select" because (as I read in -Butenhof) it isn't part of POSIX. - -Effectively, the only cancelation points that pthreads-win32 can -recognise are those the library implements itself, ie. - - pthread_testcancel - pthread_cond_wait - pthread_cond_timedwait - pthread_join - sem_wait - pthread_delay_np - -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) - -Regards. -Ross - ------------------------------------------------------------------------------- - - -Q 10 How do I create thread-safe applications using ----- pthreadGCE.dll, libpthreadw32.a and Mingw32? - -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 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 exit 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. 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.
+
+Async cancelation should be in versions post snapshot-1999-11-02
+of pthreads-win32 (currently only for x86 architectures).
+
+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.
+
+However ...
+
+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). Unfortunately, there is no way to do so from
+outside the thread.
+
+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 POSIX
+threads standard list doesn't include "select" because (as I read in
+Butenhof) it isn't part of POSIX.
+
+Effectively, the only cancelation points that pthreads-win32 can
+recognise are those the library implements itself, ie.
+
+ pthread_testcancel
+ pthread_cond_wait
+ pthread_cond_timedwait
+ pthread_join
+ sem_wait
+ pthread_delay_np
+
+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)
+
+Regards.
+Ross
+
+------------------------------------------------------------------------------
+
+
+Q 10 How do I create thread-safe applications using
+---- pthreadGCE.dll, libpthreadw32.a and Mingw32?
+
+See Thomas Pfaff's email at:
+http://sources.redhat.com/ml/pthreads-win32/2002/msg00000.html
+
+------------------------------------------------------------------------------
+
|