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diff --git a/pthreads/README b/pthreads/README new file mode 100644 index 000000000..564933302 --- /dev/null +++ b/pthreads/README @@ -0,0 +1,593 @@ +PTHREADS-WIN32 +============== + +Pthreads-win32 is free software, distributed under the GNU Lesser +General Public License (LGPL). See the file 'COPYING.LIB' for terms +and conditions. Also see the file 'COPYING' for information +specific to pthreads-win32, copyrights and the LGPL. + + +What is it? +----------- + +Pthreads-win32 is an Open Source Software implementation of the +Threads component of the POSIX 1003.1c 1995 Standard (or later) +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, +plus some common and pthreads-win32 specific non-portable +routines (see README.NONPORTABLE). + +See the file "ANNOUNCE" for more information including standards +conformance details and the list of supported and unsupported +routines. + + +Prerequisites +------------- +MSVC or GNU C (MinGW32 MSys development kit) + To build from source. + +QueueUserAPCEx by Panagiotis E. Hadjidoukas + For true async cancelation of threads (including blocked threads). + This is a DLL and Windows driver that provides pre-emptive APC + by forcing threads into an alertable state when the APC is queued. + Both the DLL and driver are provided with the pthreads-win32.exe + self-unpacking ZIP, and on the pthreads-win32 FTP site (in source + and pre-built forms). Currently this is a separate LGPL package to + pthreads-win32. See the README in the QueueUserAPCEx folder for + installation instructions. + + Pthreads-win32 will automatically detect if the QueueUserAPCEx DLL + QuserEx.DLL is available and whether the driver AlertDrv.sys is + loaded. If it is not available, pthreads-win32 will simulate async + cancelation, which means that it can async cancel only threads that + are runnable. The simulated async cancellation cannot cancel blocked + threads. + + +Library naming +-------------- + +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 was to also name either the VC or GC +version (it should be arbitrary) as pthread.dll, including +pthread.lib and libpthread.a as appropriate. This is no longer +likely to happen. + +Note 4: the compatibility number was added so that applications +can differentiate between binary incompatible versions of the +libs and dlls. + +In general: + pthread[VG]{SE,CE,C}c.dll + pthread[VG]{SE,CE,C}c.lib + +where: + [VG] indicates the compiler + V - MS VC, or + G - GNU C + + {SE,CE,C} indicates the exception handling scheme + SE - Structured EH, or + CE - C++ EH, or + C - no exceptions - uses setjmp/longjmp + + c - DLL compatibility number indicating ABI and API + compatibility with applications built against + any snapshot with the same compatibility number. + See 'Version numbering' below. + +The name may also be suffixed by a 'd' to indicate a debugging version +of the library. E.g. pthreadVC2d.lib. Debugging versions contain +additional information for debugging (symbols etc) and are often not +optimised in any way (compiled with optimisation turned off). + +For example: + pthreadVSE.dll (MSVC/SEH) + pthreadGCE.dll (GNUC/C++ EH) + pthreadGC.dll (GNUC/not dependent on exceptions) + pthreadVC1.dll (MSVC/not dependent on exceptions - not binary + compatible with pthreadVC.dll) + pthreadVC2.dll (MSVC/not dependent on exceptions - not binary + compatible with pthreadVC1.dll or pthreadVC.dll) + +The GNU library archive file names have correspondingly changed to: + + libpthreadGCEc.a + libpthreadGCc.a + + +Versioning numbering +-------------------- + +Version numbering is separate from the snapshot dating system, and +is the canonical version identification system embedded within the +DLL using the Microsoft version resource system. The versioning +system chosen follows the GNU Libtool system. See +http://www.gnu.org/software/libtool/manual.html section 6.2. + +See the resource file 'version.rc'. + +Microsoft version numbers use 4 integers: + + 0.0.0.0 + +Pthreads-win32 uses the first 3 following the Libtool convention. +The fourth is commonly used for the build number, but will be reserved +for future use. + + current.revision.age.0 + +The numbers are changed as follows: + +1. If the library source code has changed at all since the last update, + then increment revision (`c:r:a' becomes `c:r+1:a'). +2. If any interfaces have been added, removed, or changed since the last + update, increment current, and set revision to 0. +3. If any interfaces have been added since the last public release, then + increment age. +4. If any interfaces have been removed or changed since the last public + release, then set age to 0. + + +DLL compatibility numbering is an attempt to ensure that applications +always load a compatible pthreads-win32 DLL by using a DLL naming system +that is consistent with the version numbering system. It also allows +older and newer DLLs to coexist in the same filesystem so that older +applications can continue to be used. For pre .NET Windows systems, +this inevitably requires incompatible versions of the same DLLs to have +different names. + +Pthreads-win32 has adopted the Cygwin convention of appending a single +integer number to the DLL name. The number used is based on the library +version number and is computed as 'current' - 'age'. + +(See http://home.att.net/~perlspinr/libversioning.html for a nicely +detailed explanation.) + +Using this method, DLL name/s will only change when the DLL's +backwards compatibility changes. Note that the addition of new +'interfaces' will not of itself change the DLL's compatibility for older +applications. + + +Which of the several dll versions to use? +----------------------------------------- +or, +--- +What are all these pthread*.dll and pthread*.lib files? +------------------------------------------------------- + +Simple, use either pthreadGCv.* if you use GCC, or pthreadVCv.* if you +use MSVC - where 'v' is the DLL versioning (compatibility) number. + +Otherwise, you need to choose carefully and know WHY. + +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. The default version uses +setjmp/longjmp. + +There is some contension amongst POSIX threads experts as +to how POSIX threads cancelation and exit should work +with languages that use exceptions, 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 +for the reason that 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 differently when linked with other pthreads libraries. + +Now you may be asking: then 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 it would be difficult + to find. +- 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. + +Notes: + +[If you use either pthreadVCE or pthreadGCE] + +1. [See also the discussion in the FAQ file - Q2, Q4, and Q5] + +If your application contains catch(...) blocks in your POSIX +threads then you will need to replace the "catch(...)" with the macro +"PtW32Catch", eg. + + #ifdef PtW32Catch + PtW32Catch { + ... + } + #else + catch(...) { + ... + } + #endif + +Otherwise neither pthreads cancelation nor pthread_exit() will work +reliably when using versions of the library that use C++ exceptions +for cancelation and thread exit. + +This is due to what is believed to be a C++ compliance error in VC++ +whereby you may not have multiple handlers for the same exception in +the same try/catch block. GNU G++ doesn't have this restriction. + + +Other name changes +------------------ + +All snapshots prior to and including snapshot 2000-08-13 +used "_pthread_" as the prefix to library internal +functions, and "_PTHREAD_" to many library internal +macros. These have now been changed to "ptw32_" and "PTW32_" +respectively so as to not conflict with the ANSI standard's +reservation of identifiers beginning with "_" and "__" for +use by compiler implementations only. + +If you have written any applications and you are linking +statically with the pthreads-win32 library then you may have +included a call to _pthread_processInitialize. You will +now have to change that to ptw32_processInitialize. + + +Cleanup code default style +-------------------------- + +Previously, 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 short, the exceptions versions of the library throw an exception +when a thread is canceled, or exits via pthread_exit(). This exception 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 snapshot, 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/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 + +It is recommended that you let pthread.h use it's default __CLEANUP_C +for both library and application builds. That is, don't define any of +the above, and then link with pthreadVC.lib (MSVC or MSVC++) and +libpthreadGC.a (MinGW GCC or G++). The reason is explained below, but +another reason is that the prebuilt pthreadVCE.dll is currently broken. +Versions built with MSVC++ later than version 6 may not be broken, but I +can't verify this yet. + +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 pthreads platform +you use. Or at least this is the hope. + + +Building under VC++ using C++ EH, Structured EH, or just C +---------------------------------------------------------- + +From the source directory run nmake without any arguments to list +help information. E.g. + +$ nmake + +Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 +Copyright (C) Microsoft Corp 1988-1998. All rights reserved. + +Run one of the following command lines: +nmake clean VCE (to build the MSVC dll with C++ exception handling) +nmake clean VSE (to build the MSVC dll with structured exception handling) +nmake clean VC (to build the MSVC dll with C cleanup code) +nmake clean VCE-inlined (to build the MSVC inlined dll with C++ exception handling) +nmake clean VSE-inlined (to build the MSVC inlined dll with structured exception handling) +nmake clean VC-inlined (to build the MSVC inlined dll with C cleanup code) +nmake clean VC-static (to build the MSVC static lib with C cleanup code) +nmake clean VCE-debug (to build the debug MSVC dll with C++ exception handling) +nmake clean VSE-debug (to build the debug MSVC dll with structured exception handling) +nmake clean VC-debug (to build the debug MSVC dll with C cleanup code) +nmake clean VCE-inlined-debug (to build the debug MSVC inlined dll with C++ exception handling) +nmake clean VSE-inlined-debug (to build the debug MSVC inlined dll with structured exception handling) +nmake clean VC-inlined-debug (to build the debug MSVC inlined dll with C cleanup code) +nmake clean VC-static-debug (to build the debug MSVC static lib with C cleanup code) + + +The pre-built dlls are normally built using the *-inlined targets. + +You can run the testsuite by changing to the "tests" directory and +running nmake. E.g.: + +$ cd tests +$ nmake + +Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 +Copyright (C) Microsoft Corp 1988-1998. All rights reserved. + +Run one of the following command lines: +nmake clean VC (to test using VC dll with VC (no EH) applications) +nmake clean VCX (to test using VC dll with VC++ (EH) applications) +nmake clean VCE (to test using the VCE dll with VC++ EH applications) +nmake clean VSE (to test using VSE dll with VC (SEH) applications) +nmake clean VC-bench (to benchtest using VC dll with C bench app) +nmake clean VCX-bench (to benchtest using VC dll with C++ bench app) +nmake clean VCE-bench (to benchtest using VCE dll with C++ bench app) +nmake clean VSE-bench (to benchtest using VSE dll with SEH bench app) +nmake clean VC-static (to test using VC static lib with VC (no EH) applications) + + +Building under Mingw32 +---------------------- + +The dll can be built easily with recent versions of Mingw32. +(The distributed versions are built using Mingw32 and MsysDTK +from www.mingw32.org.) + +From the source directory, run make for help information. E.g.: + +$ make +Run one of the following command lines: +make clean GC (to build the GNU C dll with C cleanup code) +make clean GCE (to build the GNU C dll with C++ exception handling) +make clean GC-inlined (to build the GNU C inlined dll with C cleanup code) +make clean GCE-inlined (to build the GNU C inlined dll with C++ exception handling) +make clean GC-static (to build the GNU C inlined static lib with C cleanup code) +make clean GC-debug (to build the GNU C debug dll with C cleanup code) +make clean GCE-debug (to build the GNU C debug dll with C++ exception handling) +make clean GC-inlined-debug (to build the GNU C inlined debug dll with C cleanup code) +make clean GCE-inlined-debug (to build the GNU C inlined debug dll with C++ exception handling) +make clean GC-static-debug (to build the GNU C inlined static debug lib with C cleanup code) + + +The pre-built dlls are normally built using the *-inlined targets. + +You can run the testsuite by changing to the "tests" directory and +running make for help information. E.g.: + +$ cd tests +$ make +Run one of the following command lines: +make clean GC (to test using GC dll with C (no EH) applications) +make clean GCX (to test using GC dll with C++ (EH) applications) +make clean GCE (to test using GCE dll with C++ (EH) applications) +make clean GC-bench (to benchtest using GNU C dll with C cleanup code) +make clean GCE-bench (to benchtest using GNU C dll with C++ exception handling) +make clean GC-static (to test using GC static lib with C (no EH) applications) + + +Building under Linux using the Mingw32 cross development tools +-------------------------------------------------------------- + +You can build the library without leaving Linux by using the Mingw32 cross +development toolchain. See http://www.libsdl.org/extras/win32/cross/ for +tools and info. The GNUmakefile contains some support for this, for example: + +make CROSS=i386-mingw32msvc- clean GC-inlined + +will build pthreadGCn.dll and libpthreadGCn.a (n=version#), provided your +cross-tools/bin directory is in your PATH (or use the cross-make.sh script +at the URL above). + + +Building the library as a statically linkable library +----------------------------------------------------- + +General: PTW32_STATIC_LIB must be defined for both the library build and the +application build. The makefiles supplied and used by the following 'make' +command lines will define this for you. + +MSVC (creates pthreadVCn.lib as a static link lib): + +nmake clean VC-static + + +MinGW32 (creates libpthreadGCn.a as a static link lib): + +make clean GC-static + + +Define PTW32_STATIC_LIB when building your application. Also, your +application must call a two non-portable routines to initialise the +some state on startup and cleanup before exit. One other routine needs +to be called to cleanup after any Win32 threads have called POSIX API +routines. See README.NONPORTABLE or the html reference manual pages for +details on these routines: + +BOOL pthread_win32_process_attach_np (void); +BOOL pthread_win32_process_detach_np (void); +BOOL pthread_win32_thread_attach_np (void); // Currently a no-op +BOOL pthread_win32_thread_detach_np (void); + + +The tests makefiles have the same targets but only check that the +static library is statically linkable. They don't run the full +testsuite. To run the full testsuite, build the dlls and run the +dll test targets. + + +Building the library under Cygwin +--------------------------------- + +Cygwin is implementing it's own POSIX threads routines and these +will be the ones to use if you develop using Cygwin. + + +Ready to run binaries +--------------------- + +For convenience, the following ready-to-run files can be downloaded +from the FTP site (see under "Availability" below): + + pthread.h + semaphore.h + sched.h + pthreadVC.dll - built with MSVC compiler using C setjmp/longjmp + pthreadVC.lib + pthreadVCE.dll - built with MSVC++ compiler using C++ EH + pthreadVCE.lib + pthreadVSE.dll - built with MSVC compiler using SEH + pthreadVSE.lib + pthreadGC.dll - built with Mingw32 GCC + libpthreadGC.a - derived from pthreadGC.dll + pthreadGCE.dll - built with Mingw32 G++ + libpthreadGCE.a - derived from pthreadGCE.dll + +As of August 2003 pthreads-win32 pthreadG* versions are built and tested +using the MinGW + MsysDTK environment current as of that date or later. +The following file MAY be needed for older MinGW environments. + + gcc.dll - needed to build and run applications that use + pthreadGCE.dll. + + +Building applications with GNU compilers +---------------------------------------- + +If you're using pthreadGC.dll: + +With the three header files, pthreadGC.dll and libpthreadGC.a in the +same directory as your application myapp.c, you could compile, link +and run myapp.c under Mingw32 as follows: + + gcc -o myapp.exe myapp.c -I. -L. -lpthreadGC + myapp + +Or put pthreadGC.dll in an appropriate directory in your PATH, +put libpthreadGC.a in your system lib directory, and +put the three header files in your system include directory, +then use: + + gcc -o myapp.exe myapp.c -lpthreadGC + myapp + + +If you're using pthreadGCE.dll: + +With the three header files, pthreadGCE.dll, gcc.dll and libpthreadGCE.a +in the same directory as your application myapp.c, you could compile, +link and run myapp.c under Mingw32 as follows: + + gcc -x c++ -o myapp.exe myapp.c -I. -L. -lpthreadGCE + myapp + +Or put pthreadGCE.dll and gcc.dll in an appropriate directory in +your PATH, put libpthreadGCE.a in your system lib directory, and +put the three header files in your system include directory, +then use: + + gcc -x c++ -o myapp.exe myapp.c -lpthreadGCE + myapp + + +Availability +------------ + +The complete source code in either unbundled, self-extracting +Zip file, or tar/gzipped format can be found at: + + ftp://sources.redhat.com/pub/pthreads-win32 + +The pre-built DLL, export libraries and matching pthread.h can +be found at: + + ftp://sources.redhat.com/pub/pthreads-win32/dll-latest + +Home page: + + http://sources.redhat.com/pthreads-win32/ + + +Mailing list +------------ + +There is a mailing list for discussing pthreads on Win32. +To join, send email to: + + pthreads-win32-subscribe@sources.redhat.com + +Unsubscribe by sending mail to: + + pthreads-win32-unsubscribe@sources.redhat.com + + +Acknowledgements +---------------- + +See the ANNOUNCE file for acknowledgements. +See the 'CONTRIBUTORS' file for the list of contributors. + +As much as possible, the ChangeLog file attributes +contributions and patches that have been incorporated +in the library to the individuals responsible. + +Finally, thanks to all those who work on and contribute to the +POSIX and Single Unix Specification standards. The maturity of an +industry can be measured by it's open standards. + +---- +Ross Johnson +<rpj@callisto.canberra.edu.au> + + + + + + + + |