[ViewVC] Annotation of: cvs/IO-AIO/Changes

Revision history for IO::AIO

TODO: better autoconf.pm that can return LIBS etc.
TODO: aio_cptree/mvtree
TODO: reduce condvar fairness: schedule hot-cache-threads first?
TODO: splice/tee/vmsplice/sync_file_range? (http://kerneltrap.org/node/6505 http://lwn.net/Articles/178199/)
TODO: aio_fcntl, at least for file-locking

        - port to solaris perls configured for old posix
          (analysed by Jost Krieger).

2.61 Wed Apr 16 18:45:02 CEST 2008
        - fix treescan output duplication and improve output ordering.
          also display files given on the commandline.
        - use a different algorithm for aio_close that is faster
          and probably has even lower chances of blocking.
        - do our own stack memory management for threads - linux
          allocates outrageous amounts of VM (not so bad unless you
          use mlockall...), which severely limits the number of threads
          on 32-bit arches: stack size is the larger of PTHREAD_STACK_MIN
          and 4096 * sizeof (long) (usually this is 16..64k).

2.6  Sun Mar 30 08:28:11 CEST 2008
        - added aio_sync.
        - added aio_pathsync.
        - fix prototypes of (void) functions.

2.51 Sat Oct  6 16:04:54 CEST 2007
        - perlio isn't generally threadsafe, so aio_close could not work reliably.
          aio_close now tries a safe hack that might not be that asynchronous
          (see the manpage for details).
        - discard callback return values as to not grow the stack endlessly
          when poll_cb handles many requests without returning.
        - minor code cleanups.

2.5  Thu Oct  4 14:49:08 CEST 2007
        - replaced _fd2fh with faster xs code.
        - aio_close will now try to do "the right thing" and thus might
          work sensibly for the very first time.

2.41 Mon Sep 24 21:28:21 CEST 2007
        - after fork, invest some work to make sure that the poll_fileno
          stays stable (by dup2'ing the new fd over the old one), to make
          it easier for programs/libs that don't control their forking
          behaviour and cannot recreate their watchers.

2.4  Sun Aug  5 18:44:22 CEST 2007
        - add aio_truncate, aio_chmod, aio_chown, aio_utime (linux
          successfully demonstrated that you can block on futimes...).
        - allow undef as fileoffset for aio_read/write and use read/write(2)
          internally (useful for sockets or O_APPEND handles).
        - allow undef for length in aio_write.
        - negative dataoffsets work as expected now in aio_read/aio_write.
        - use NV instead of UV for 32 bit perls and file offsets, as NVs
          have a larger range then.
        - shared code between BDB and IO::AIO.
        - aio_busy was completely broken. now fixed.
        - readahead emulation now returns something.
        - correctly set errno to ENOSYS on unimplemented functions
          (should never happen, though).
        - large changes to make it partially compile and run on win32,
          but win32 lacks too much functionality, and perl overrides way
          too many functions with crashing versions.

2.33 Tue Jan 23 23:55:41 CET 2007
        - fix install path (Andreas J. Koenig).

2.32 Mon Jan 22 16:56:23 CET 2007
        - added aio_rmtree.
        - wow, aio_mkdir was missing.
        - aio_load did return undef on error, not -1.
        - use prefixexp not prefix in autoconf.pm
          (suggested by ... rt.cpan.org unreachable).
        - avoid installing autoconf.pm.

2.31 Sat Jan  6 03:46:02 CET 2007
        - added aio_load.

2.3  Sat Dec 23 05:48:07 CET 2006
        - fix off-by-one bug in aio_read, causing memory corruption
          or crashes.

2.21  Fri Dec 22 05:03:38 CET 2006
        - minor doc updates.
        - minor cleanups.
        - IO::AIO::poll returns request count.
        - undocumented and unfinished async-signal-reporting.

2.2  Tue Oct 31 00:31:00 CET 2006
        - minor doc updates.
        - added aio_readlink.
        - properly zero-terminate aio_read buffer.
        - fix aio_read/write with nonzero dataoffset.
        - reduced size of aio request structure.
        - better diagnostics when pathnames etc. are not byte-encoded;
          do not leak request in that case, either.

2.1  Sun Oct 29 02:01:57 CET 2006
        - INCOMPATIBLE CHANGE: replace IO::AIO::poll_some by
          IO::AIO::max_poll_reqs and IO::AIO::max_poll_time.
        - fix a bug in aio_move where it would fail everytime
          it would have to copy files manually.
        - doc updates.
        - start threads only on (very low) demand.
        - end superfluous threads automatically after 10s idling.
        - add IO::AIO::max_idle to control this.
        - some tuning applied to random places.
        - add aio_mknod.

2.0  Thu Oct 26 18:27:58 CEST 2006
        - minor incompatibility: max_outstanding semantics have changed.
        - major rewrite, consider all functionality EXPERIMENTAL.
        - aio requests can be cancelled.
        - callbacks can be (re-)set later.
        - aio requests can choose between 9 priorities.
        - add aio_group: aio requests can be grouped
          into composite requests.
        - generator interface for groups.
        - add IO::AIO::poll_some.
        - major documentation improvements.
        - very minor bugfixes.
        - add aio_nop for dummy requests.
        - add aio_busy mainly for benchmarking and debugging.
        - use "fast" mutexes on linux.
        - use dynamic (and larger) buffers instead of
          putting them onto the stack.
        - optimise x86 and amd64 a bit.
        - better error checking when ENOMEM.
        - hopefully fix mem and dirp leaks on fork.
        - warn about broken perl malloc.
        - compiles on cygwin (but pread is broken on cygwin
          which is not detected by autoconf, so you have to
          edit autoconf/config.h yourself to enable emulation).

1.8  Sat Jun 24 22:20:44 CEST 2006
        - add and/or document aio_rename, aio_link, aio_symlink and aio_move.

1.73 Wed Mar  1 22:49:32 CET 2006
        - codename "jost"
        - AIX/Solaris(?) aren't being helpful again, hardcode a value
          for NAME_MAX and drive with your eyes closed (reported by
          wcooley@nakedape.cc).

1.72 Thu Feb  2 00:40:44 CET 2006
        - another minor bug in aio_scandir, again, the callback was called
          twice when the directory can't be stat'ed.

1.71 Mon Dec 26 20:20:03 CET 2005
        - grr, another minor bug in aio_scandir, this time resulting
          in a runtime error.

1.7  Mon Dec 26 19:29:48 CET 2005
        - aio_scandir errornously called callback twice in some cases.
        - added AnyEvent example.

1.61 Wed Sep  7 19:40:42 CEST 2005
        - no longer include $Config{libs}, as distros include too much
          garbage in there that is not installed on typical systems
          (for example, debian links perl against -lgdbm and many more
          libraries despite perl not needing it, slowing down startup and
          wasting memory).

1.6  Tue Aug 30 17:44:44 CEST 2005
        - added aio_readdir, aio_scandir.
        - added aio_sendfile, including sendfile emulation when sendfile
          isn't available. Linux, FreeBSD and HP-UX might work (sendfilev
          support is unavailable on my solaris 8 machine, but preliminary
          code is there. What's lacking is configury stuff and testing...).

1.5  Sat Aug 20 02:32:19 CEST 2005
        - create the aio threads on demand only (good after forking).
        - somebody nagged about C89 compatibility, so this release should
          be C89 compatible, but no guarantees for future ones.
        - abort when the configure script fails.

1.4  Wed Aug 17 08:07:27 CEST 2005
        - forgot to recreate the pipe after forking, this could cause
          deadlocks.

1.3  Wed Aug 17 07:25:54 CEST 2005
        - properly propagate exceptions from callbacks, instead of silently
          eating them.
        - use a different fork algorithm that avoids recursive callback
          invocations and reduces fork latency in busy processes.
        - fix a bug where the buffer scalar in aio_read got assigned the wrong
          length after reading.
        - fix a bug where the child would process some outstanding requests
          from the parent.
        - make a copy of the callback scalar, to avoid some very uncommon
          (but valid) usages where the callback scalar changes.
        - the callback was never freed in aio_read/aio_write.
        - aio_read/aio_write will now set the readonly flag on the data
          scalar for better error reporting.

1.2  Wed Aug 17 01:22:58 CEST 2005
        - verified on cygwin, linux/amd64+ia32+alpha, solaris.
        - use SvPVbyte for filenames now. You *need* to encode your strings to
          the external filename encoding first.
        - fix the bug where filehandles could leak (again).
        - clarify freebsd situation: make it work and tell me how, or go away
          with your underdocumented, broken and outdated OS.
        - fork'ing should now be officially supported (where linux and
          posix contradict each other, I followed posix).
        - only call read() once per poll, not twice (speedup).
        - new functions: aio_rmdir, aio_symlink.
        - force callback arguments to be undef or a reference, for better
          error catching.

1.1  Sun Aug  7 05:27:23 CEST 2005
        - added configure script to detect availability of some calls.
          (imperfect, as we cannot detect things like -lrt due to missing
          feedback yet).
        - emulate fdatasync via fsync, pread/pwrite via unsafe read/write
          and readahead via manual reading on platforms lacking those.
        - ported t/03_errors.t+framework by Brad Fitzpatrick
          from Linux::AIO.
        - removed XOPEN_SOURCE because stupid solaris 9 doesn't
          compile with it enabled. Probably breaks others. Oh well.
        - try to be more careful with errno on non-threaded perls.
        - cygwins perl insisted on a matching open mode when morphing
          the fd to an fh.
        - convert sv's to "byte" encoding in aio_read/aio_write. Might
          do that for pathnames, too, in the future, so make sure you
          properly encode your pathnames.

1.0  Fri Jul 22 10:43:30 CEST 2005
        - aio_open did not reliably deliver (open) filehandles.
        - all aio_*-functions keep a reference to the filehandle so
          it doesn't go away while the aio requests is working on it.
        - disable warnings in AIO.pm.

0.9  Wed Jul 20 23:55:04 CEST 2005
        - allow recursive calls to poll_cb, use less locking calls, too.
        - fix the Gtk2-example in the SYNOPSIS.
        - use pread/pwrite not pread64/pwrite64. this was simply a leftover
          from Linux::AIO.
          (found by compiling on cygwin. Unfortunately, cygwin declares but
          does not implement pread/pwrite).
        - only include <sys/syscall.h> on linux.

0.5  Tue Jul 12 13:03:09 CEST 2005
        - removed #include <endian.h>, it's not portable, and we don't
          need it anyway.
        - link against -lrt, as it might contain goodies such as fdatasync,
          and often aio_read, which we do not use yet, but it shouldn't hurt.

0.4  Mon Jul 11 05:28:25 CEST 2005
        - added IO::AIO::flush, IO::AIO::poll.
        - make callback argument optional for all calls.

0.3  Mon Jul 11 01:42:37 CEST 2005
        - restructured manpage.
        - added SYNOPSIS with examples for Event, Glib, Tk.
        - remove explicit context support so I don't have to maintain
          it for threaded perls (i.e. it should work now :).

0.2  Sun Jul 10 22:57:12 CEST 2005
        - return immediately from poll_wait if nreqs==0.
        - get rid of the request pipe and use faster thread-thread
          communications for most requests and responses.

0.1
        - cloned from Linux::AIO, which is very similar.

Revision:	1.141
Committed:	Mon Apr 21 20:09:41 2008 UTC (16 years ago) by root
Branch:	MAIN
Changes since 1.140:	+3 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.31	Revision history for IO::AIO
2	root	1.30
3	root	1.59	TODO: better autoconf.pm that can return LIBS etc.
4	root	1.114	TODO: aio_cptree/mvtree
5	root	1.106	TODO: reduce condvar fairness: schedule hot-cache-threads first?
6	root	1.123	TODO: splice/tee/vmsplice/sync_file_range? (http://kerneltrap.org/node/6505 http://lwn.net/Articles/178199/)
7	root	1.136	TODO: aio_fcntl, at least for file-locking
8	root	1.100
9	root	1.141	- port to solaris perls configured for old posix
10			(analysed by Jost Krieger).
11
12	root	1.140	2.61 Wed Apr 16 18:45:02 CEST 2008
13	root	1.137	- fix treescan output duplication and improve output ordering.
14			also display files given on the commandline.
15	root	1.140	- use a different algorithm for aio_close that is faster
16			and probably has even lower chances of blocking.
17	root	1.138	- do our own stack memory management for threads - linux
18			allocates outrageous amounts of VM (not so bad unless you
19			use mlockall...), which severely limits the number of threads
20	root	1.139	on 32-bit arches: stack size is the larger of PTHREAD_STACK_MIN
21			and 4096 * sizeof (long) (usually this is 16..64k).
22	root	1.137
23	root	1.136	2.6 Sun Mar 30 08:28:11 CEST 2008
24	root	1.134	- added aio_sync.
25	root	1.135	- added aio_pathsync.
26	root	1.136	- fix prototypes of (void) functions.
27	root	1.134
28	root	1.133	2.51 Sat Oct 6 16:04:54 CEST 2007
29			- perlio isn't generally threadsafe, so aio_close could not work reliably.
30			aio_close now tries a safe hack that might not be that asynchronous
31			(see the manpage for details).
32			- discard callback return values as to not grow the stack endlessly
33			when poll_cb handles many requests without returning.
34			- minor code cleanups.
35
36	root	1.132	2.5 Thu Oct 4 14:49:08 CEST 2007
37	root	1.131	- replaced _fd2fh with faster xs code.
38			- aio_close will now try to do "the right thing" and thus might
39			work sensibly for the very first time.
40
41	root	1.130	2.41 Mon Sep 24 21:28:21 CEST 2007
42	root	1.129	- after fork, invest some work to make sure that the poll_fileno
43			stays stable (by dup2'ing the new fd over the old one), to make
44			it easier for programs/libs that don't control their forking
45			behaviour and cannot recreate their watchers.
46
47	root	1.128	2.4 Sun Aug 5 18:44:22 CEST 2007
48	root	1.127	- add aio_truncate, aio_chmod, aio_chown, aio_utime (linux
49			successfully demonstrated that you can block on futimes...).
50	root	1.124	- allow undef as fileoffset for aio_read/write and use read/write(2)
51			internally (useful for sockets or O_APPEND handles).
52	root	1.126	- allow undef for length in aio_write.
53			- negative dataoffsets work as expected now in aio_read/aio_write.
54	root	1.124	- use NV instead of UV for 32 bit perls and file offsets, as NVs
55	root	1.125	have a larger range then.
56	root	1.120	- shared code between BDB and IO::AIO.
57	root	1.127	- aio_busy was completely broken. now fixed.
58			- readahead emulation now returns something.
59	root	1.121	- correctly set errno to ENOSYS on unimplemented functions
60			(should never happen, though).
61	root	1.127	- large changes to make it partially compile and run on win32,
62			but win32 lacks too much functionality, and perl overrides way
63			too many functions with crashing versions.
64	root	1.120
65	root	1.119	2.33 Tue Jan 23 23:55:41 CET 2007
66			- fix install path (Andreas J. Koenig).
67
68	root	1.118	2.32 Mon Jan 22 16:56:23 CET 2007
69	root	1.114	- added aio_rmtree.
70	root	1.115	- wow, aio_mkdir was missing.
71	root	1.116	- aio_load did return undef on error, not -1.
72	root	1.117	- use prefixexp not prefix in autoconf.pm
73			(suggested by ... rt.cpan.org unreachable).
74	root	1.118	- avoid installing autoconf.pm.
75	root	1.114
76	root	1.113	2.31 Sat Jan 6 03:46:02 CET 2007
77	root	1.112	- added aio_load.
78
79	root	1.111	2.3 Sat Dec 23 05:48:07 CET 2006
80			- fix off-by-one bug in aio_read, causing memory corruption
81			or crashes.
82
83	root	1.110	2.21 Fri Dec 22 05:03:38 CET 2006
84	root	1.108	- minor doc updates.
85	root	1.107	- minor cleanups.
86			- IO::AIO::poll returns request count.
87	root	1.109	- undocumented and unfinished async-signal-reporting.
88	root	1.107
89	root	1.103	2.2 Tue Oct 31 00:31:00 CET 2006
90	root	1.100	- minor doc updates.
91	root	1.101	- added aio_readlink.
92			- properly zero-terminate aio_read buffer.
93			- fix aio_read/write with nonzero dataoffset.
94	root	1.104	- reduced size of aio request structure.
95	root	1.106	- better diagnostics when pathnames etc. are not byte-encoded;
96	root	1.105	do not leak request in that case, either.
97	root	1.94
98	root	1.99	2.1 Sun Oct 29 02:01:57 CET 2006
99	root	1.98	- INCOMPATIBLE CHANGE: replace IO::AIO::poll_some by
100			IO::AIO::max_poll_reqs and IO::AIO::max_poll_time.
101	root	1.95	- fix a bug in aio_move where it would fail everytime
102			it would have to copy files manually.
103	root	1.98	- doc updates.
104	root	1.94	- start threads only on (very low) demand.
105	root	1.97	- end superfluous threads automatically after 10s idling.
106	root	1.98	- add IO::AIO::max_idle to control this.
107	root	1.94	- some tuning applied to random places.
108	root	1.95	- add aio_mknod.
109	root	1.59
110	root	1.92	2.0 Thu Oct 26 18:27:58 CEST 2006
111	root	1.90	- minor incompatibility: max_outstanding semantics have changed.
112	root	1.86	- major rewrite, consider all functionality EXPERIMENTAL.
113	root	1.68	- aio requests can be cancelled.
114	root	1.81	- callbacks can be (re-)set later.
115	root	1.93	- aio requests can choose between 9 priorities.
116	root	1.83	- add aio_group: aio requests can be grouped
117			into composite requests.
118			- generator interface for groups.
119	root	1.89	- add IO::AIO::poll_some.
120	root	1.72	- major documentation improvements.
121			- very minor bugfixes.
122	root	1.76	- add aio_nop for dummy requests.
123	root	1.84	- add aio_busy mainly for benchmarking and debugging.
124	root	1.79	- use "fast" mutexes on linux.
125	root	1.80	- use dynamic (and larger) buffers instead of
126			putting them onto the stack.
127			- optimise x86 and amd64 a bit.
128			- better error checking when ENOMEM.
129	root	1.85	- hopefully fix mem and dirp leaks on fork.
130	root	1.92	- warn about broken perl malloc.
131	root	1.88	- compiles on cygwin (but pread is broken on cygwin
132			which is not detected by autoconf, so you have to
133			edit autoconf/config.h yourself to enable emulation).
134	root	1.68
135	root	1.67	1.8 Sat Jun 24 22:20:44 CEST 2006
136	root	1.66	- add and/or document aio_rename, aio_link, aio_symlink and aio_move.
137
138	root	1.65	1.73 Wed Mar 1 22:49:32 CET 2006
139			- codename "jost"
140			- AIX/Solaris(?) aren't being helpful again, hardcode a value
141			for NAME_MAX and drive with your eyes closed (reported by
142			wcooley@nakedape.cc).
143	root	1.63
144	root	1.62	1.72 Thu Feb 2 00:40:44 CET 2006
145	root	1.61	- another minor bug in aio_scandir, again, the callback was called
146			twice when the directory can't be stat'ed.
147
148	root	1.60	1.71 Mon Dec 26 20:20:03 CET 2005
149			- grr, another minor bug in aio_scandir, this time resulting
150			in a runtime error.
151
152	root	1.59	1.7 Mon Dec 26 19:29:48 CET 2005
153	root	1.58	- aio_scandir errornously called callback twice in some cases.
154	root	1.57	- added AnyEvent example.
155
156	root	1.55	1.61 Wed Sep 7 19:40:42 CEST 2005
157	root	1.54	- no longer include $Config{libs}, as distros include too much
158	root	1.56	garbage in there that is not installed on typical systems
159	root	1.54	(for example, debian links perl against -lgdbm and many more
160			libraries despite perl not needing it, slowing down startup and
161			wasting memory).
162
163	root	1.53	1.6 Tue Aug 30 17:44:44 CEST 2005
164			- added aio_readdir, aio_scandir.
165	root	1.51	- added aio_sendfile, including sendfile emulation when sendfile
166			isn't available. Linux, FreeBSD and HP-UX might work (sendfilev
167			support is unavailable on my solaris 8 machine, but preliminary
168			code is there. What's lacking is configury stuff and testing...).
169	root	1.46
170	root	1.44	1.5 Sat Aug 20 02:32:19 CEST 2005
171	root	1.51	- create the aio threads on demand only (good after forking).
172	root	1.41	- somebody nagged about C89 compatibility, so this release should
173	root	1.42	be C89 compatible, but no guarantees for future ones.
174	root	1.43	- abort when the configure script fails.
175	root	1.41
176	root	1.40	1.4 Wed Aug 17 08:07:27 CEST 2005
177	root	1.93	- forgot to recreate the pipe after forking, this could cause
178	root	1.40	deadlocks.
179
180	root	1.39	1.3 Wed Aug 17 07:25:54 CEST 2005
181	root	1.33	- properly propagate exceptions from callbacks, instead of silently
182			eating them.
183	root	1.38	- use a different fork algorithm that avoids recursive callback
184			invocations and reduces fork latency in busy processes.
185	root	1.37	- fix a bug where the buffer scalar in aio_read got assigned the wrong
186			length after reading.
187			- fix a bug where the child would process some outstanding requests
188			from the parent.
189			- make a copy of the callback scalar, to avoid some very uncommon
190			(but valid) usages where the callback scalar changes.
191			- the callback was never freed in aio_read/aio_write.
192	root	1.38	- aio_read/aio_write will now set the readonly flag on the data
193			scalar for better error reporting.
194	root	1.33
195	root	1.32	1.2 Wed Aug 17 01:22:58 CEST 2005
196			- verified on cygwin, linux/amd64+ia32+alpha, solaris.
197	root	1.31	- use SvPVbyte for filenames now. You need to encode your strings to
198			the external filename encoding first.
199	root	1.32	- fix the bug where filehandles could leak (again).
200	root	1.31	- clarify freebsd situation: make it work and tell me how, or go away
201			with your underdocumented, broken and outdated OS.
202			- fork'ing should now be officially supported (where linux and
203			posix contradict each other, I followed posix).
204	root	1.32	- only call read() once per poll, not twice (speedup).
205			- new functions: aio_rmdir, aio_symlink.
206	root	1.31	- force callback arguments to be undef or a reference, for better
207			error catching.
208	root	1.1
209	root	1.29	1.1 Sun Aug 7 05:27:23 CEST 2005
210	root	1.25	- added configure script to detect availability of some calls.
211	root	1.27	(imperfect, as we cannot detect things like -lrt due to missing
212	root	1.23	feedback yet).
213	root	1.27	- emulate fdatasync via fsync, pread/pwrite via unsafe read/write
214			and readahead via manual reading on platforms lacking those.
215	root	1.19	- ported t/03_errors.t+framework by Brad Fitzpatrick
216			from Linux::AIO.
217	root	1.18	- removed XOPEN_SOURCE because stupid solaris 9 doesn't
218			compile with it enabled. Probably breaks others. Oh well.
219	root	1.24	- try to be more careful with errno on non-threaded perls.
220	root	1.26	- cygwins perl insisted on a matching open mode when morphing
221			the fd to an fh.
222	root	1.28	- convert sv's to "byte" encoding in aio_read/aio_write. Might
223			do that for pathnames, too, in the future, so make sure you
224			properly encode your pathnames.
225	root	1.18
226	root	1.17	1.0 Fri Jul 22 10:43:30 CEST 2005
227			- aio_open did not reliably deliver (open) filehandles.
228	root	1.16	- all aio_*-functions keep a reference to the filehandle so
229			it doesn't go away while the aio requests is working on it.
230			- disable warnings in AIO.pm.
231
232	root	1.15	0.9 Wed Jul 20 23:55:04 CEST 2005
233			- allow recursive calls to poll_cb, use less locking calls, too.
234			- fix the Gtk2-example in the SYNOPSIS.
235	root	1.14	- use pread/pwrite not pread64/pwrite64. this was simply a leftover
236			from Linux::AIO.
237			(found by compiling on cygwin. Unfortunately, cygwin declares but
238			does not implement pread/pwrite).
239			- only include <sys/syscall.h> on linux.
240
241	root	1.13	0.5 Tue Jul 12 13:03:09 CEST 2005
242	root	1.12	- removed #include <endian.h>, it's not portable, and we don't
243			need it anyway.
244			- link against -lrt, as it might contain goodies such as fdatasync,
245			and often aio_read, which we do not use yet, but it shouldn't hurt.
246
247	root	1.11	0.4 Mon Jul 11 05:28:25 CEST 2005
248	root	1.9	- added IO::AIO::flush, IO::AIO::poll.
249	root	1.10	- make callback argument optional for all calls.
250	root	1.8
251	root	1.7	0.3 Mon Jul 11 01:42:37 CEST 2005
252	root	1.5	- restructured manpage.
253	root	1.7	- added SYNOPSIS with examples for Event, Glib, Tk.
254			- remove explicit context support so I don't have to maintain
255			it for threaded perls (i.e. it should work now :).
256	root	1.5
257	root	1.4	0.2 Sun Jul 10 22:57:12 CEST 2005
258	root	1.2	- return immediately from poll_wait if nreqs==0.
259			- get rid of the request pipe and use faster thread-thread
260	root	1.3	communications for most requests and responses.
261	root	1.2
262	root	1.1	0.1
263			- cloned from Linux::AIO, which is very similar.
264