Revision history for IO::AIO

TODO: scandir - some dirs mostly contain subdirs - invert logic?
TODO: aio_cptree/mvtree
TODO: vmsplice? (
TODO: getxattr, setxattr, listxattr, removexattr etc.?
TODO: emulation for splice?
TODO: syncfs/sync windows:
TODO: posix_fallocate when flags=0
TODO: extra socket/tcp constants &c?
TODO: name_to_handle_At + open_by_handle_at = clone fds
TODO: lchown
TODO: mount/umount2/MS_* flags
TODO: fsmount/fspick/fsconfig/fsmount et al.

TODO: rewrite rmtree et al. to support working directories (also speed them up)
TODO: maybe IO::AIO leaks fds when requests are cancelled? maybe initialise result to -1?
TODO: aio_wd should use O_PATH on linux, due to lacking O_SEARCH (
TODO: mincore
TODO: unlinkat flags, linkat flags, statat, renameat2 flags
TODO: define useful rules for [[$wd, $path], $path] &c and implement them
TODO: dup3, pipe2, accept4
TODO: dump config.log when automated testign and configure fails
TODO: ns time resolution in utime
TODO: statx
TODO: pidfd_open/pidfd_send_signal (open/poll /proc?)
TODO: aio_fchdir/chdir? emulate chdirat?
TODO: aio_splice, aio_tee
TODO: copy_file_range
TODO: write more abpout the thread model, maybe bump some defaults?
TODO: io_uring, but it's so broken  :/
TODO: allow import of fds as aio_wd
TODO: close_range
TODO: move_mount, open_tree

4.75 Wed Dec 30 08:44:55 CET 2020
	- removed leftover debug output from treescan.
	- added (but not documented) waitid-P_*, FSPICK_*, FSOPEN_*,
          FSCONFIG_*, MOUNT_ATTR_* constants.

4.74 Tue Dec 29 16:19:28 CET 2020
	- added pidfd_open, pidfd_getfd and pidfd_send_signal functions.
        - rework bin/treescan to avoid recursion. This fixes two bugs
          where a deep directory traversal or a lot of command line
          arguments could cause it to crash.
	- added (but not documented) open_tree, AT_* and move_mount flags.
        - support defining syscall numbers in gendef0.

4.73 Fri Dec  4 02:08:37 CET 2020
	- def0.h was not uptodate, running into musl problems
          (reported by B Fraser).
	- IO::AIO::splice and IO::AIO::tee didn't properly return
          64 bit values.
	- added IO::AIO::accept4.
	- add various F_SEAL related fcntl constants.
        - removed experimental marker for fdlimit functions.
        - fiemap now includes the last segment even if it overflows
          the end offset, which is arguably the correct behaviour.

4.72 Wed Apr  3 04:56:03 CEST 2019
        - (libeio) if fd 0 is available do not use it for aio_wd, as it
          collides with IO::AIO::CWD.
	- added IO::AIO::memfd_create.
	- correctly include <sys/uio.h> in the vmsplice test.
        - reduce codesize by ~7% on amd64 by declaring more functions
          as noinline.
        - documentation fixes and updates.
        - experimental and undocumented preliminary support for synchronous statx.

4.71 Sun Mar 10 13:09:26 CET 2019
	- due to an error in the linux manpages, the configure tests
          for readahead, sync_file_range, splice etc. failed. This has been fixed.

4.7  Mon Mar  4 11:28:13 CET 2019
	- majorly speed up scandir for the very special case of a non-POSIX
          filesystem that nevertheless reports valid dt_type information.
          The only known filesystem of this type is currently btrfs, which
          didn't get it's act together to implement POSIX semantics in all
          these years, and I am tired of waiting.
	- add IO::AIO::MCL_ONFAULT for mlockall, add IO::AIO::mlockall.
	- neither sys/mkdev.h nor sys/sysmacros.h were included, even when they
          were detected by autoconf.

4.6  Sat Aug 25 21:58:36 CEST 2018
	- add st_btime, st_btimesec, st_btimensec and st_gen accessors,
          mostly for bsds which expose birthtime and st_gen members (netbsd, freebsd
          but only st_gen on openbsd because they compiled their perl without support
          for birthtimes).
        - fix madvise and munlock to properly support negative offsets.
        - allocate fd for the aio_close at boot time, to guarantee it working
          later, rather than calling abort when it fails. also avoids
          close-on-exec race issues after module load.
        - #undef utime on win32, maybe this helps some reports of utime hangs.
        - minor doc improvements.
        - minor configure cleanups.
        - use $Config{perllibs} instead of libs for configure. might help people
          who didn't install all perl dependencies (might break things as well).

4.54 Tue Aug 14 13:54:48 CEST 2018
	- include sys/mkdev.h or sys/sysmacros.h if available.
        - further tweaks to configure invocation for systems requiring --rpath.
        - no longer rely on custom paths on win32 platforms.
        - try to work around buggy PAGESIZE macro on solaris.

4.53 Tue Aug 14 11:27:50 CEST 2018
	- add $Config{libs} to LIBS for configure, to work around systems
          with broken library dependencies (... openbsd).

4.52 Sun Aug 12 08:09:45 CEST 2018
	- was missing in distribution.

4.51 Sun Aug 12 07:24:14 CEST 2018
	- complete rework of the autoconf framework: IO::AIO now uses its own
          config.h, separate from libeio, and tries to test the actual perl
          environment, not the standard system environment.
        - provide nanosecond-accracy stat time accessors for both perl and IO::AIO
          stat functions.
	- removed non-portable C++ syntax from eio.c.
        - try to fix readdir tests on cygwin spuriously failing.

4.5  Wed Aug  1 00:23:55 CEST 2018
	- aio_mtouch touch all pages as requested, not just the first page in most cases.
        - new function: IO::AIO::mremap, linux-specific mremap, with constants MREMAP_MAYMOVE
          and MREMAP_FIXED.
        - add O_ACCMODE.
	- add (undocumented) MSG_CMSG_CLOEXEC and SOCK_CLOEXEC constants.

4.4   Tue Feb 20 07:54:12 CET 2018
	- new aio_slurp request.
        - add (experimental) IO::AIO::eventfd and timerfd* function.
	- add (experimental) IO::AIO::get_fdlimit and IO::AIO::min_fdlimit.
        - point out that aio_copy overwrites existing files.
        - removed filesystem magic number table from aio_statvfs docs as
          statvfs doesn't actually return this info at all (statfs does).
        - add a bunch of (mostly linux-specific) constants for use in ioctls
          (see aio_ioctl docs).
        - treescan now has a proper manpage and useful --help output.
        - new option --sync in treescan, to sync everything in a subtree.
        - changed default for aio_msync flags to MSYNC_SYNC.
        - document offset/length behaviour of mprotect/madvise.
        - support linux's renameat2 (via aio_rename2).
        - add aio_rename2, an aio_rename with flags.
        - add F_DUPPFD_CLOEXEC, F_OFD_[SG]ETLKW? constants.
        - (libeio) use posix_close if available.
        - (libeio) internal close() calls no longer disturb errno.
        - add IO:AIO::FALLOC_FL_UNSHARE.
        - update schmorp.h for removal of USE_SOCKETS_AS_HANDLES
          and better eventfd detection.

4.34  Sun May  1 19:18:24 CEST 2016
	- def0.h was not properly generated during previous release, causing
          compile errors on various platforms.
	- major/minor were accidentally switched (reported by Alexander Lishenyuk).
	- removed duplicate definition of MAP_HUGETLB, that was found due to
          a bug in Perl::Tidy (testcase by
        - added (untested!) aio_fcntl, aio_ioctl requests.
        - (libeio) names set via prctl are truncated to 15 chars + nul, not 16,
          as manpages-dev originally claimed.

4.33  Mon Jan 18 12:50:10 CET 2016
	- add IO::AIO::pipe2 function.
        - added support for FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_ZERO_RANGE
        - added support for O_TMPFILE and O_PATH constants.
          consdtants, whether they can be sensibly used or not.
	- use NO_INIT where applicable.
        - update libecb.
        - added stability canary support.
        - updated linux super magic table to 4.3.3.

4.32  Wed Feb 11 20:32:11 CET 2015
	- replace off_t by STRLEN where appropriate, should not result in
          user-visible changes.
        - update ecb.h for C11 compatibility.

4.31  Tue Jun  3 03:29:27 CEST 2014
	- work around more 5.20 bugs. backwards compatibility my ass.

4.3   Fri Apr 11 06:22:38 CEST 2014
	- perl5porters broke Async::Interrupt, BDB, EV, IO::AIO, OpenCL
          without warning by switching the meaning of USE_SOCKETS_AS_HANDLES
          in 5.18. What's so attractive about giving a shit about backwards
          compatibility - I will never understand.

4.2   Sat Jan 25 01:13:14 CET 2014
	- aio_group could corrupt memory because it didn't restore
          the stack after req_submit.
        - be more careful on (e.g. permission) errors in bin/treescan.
	- work around changes in ExtUtils::MakeMaker.
	- (libeio) implement aio_realpath for win32.
        - (xthread) work around compile time bugs in ptw32.
        - added IO::AIO::pipesize.
        - (libecb) insignificant update.

4.19  Sun Jan  6 12:47:26 CET 2013
	- avoid endless loop in fiemap with some XFS files.
	- in aio_rename and aio_rmdir, specialcase the case of [$wd, "."]
          and call rename/rmdir instead of renameat/unlinkat.

4.18  Thu Oct 11 07:01:26 CEST 2012
	- fix unintended xthread_create by intentionalising it :)

4.17  Thu Oct 11 05:19:47 CEST 2012
        - rename aio_fallocate to aio_allocate, to match documentation.
	- add list of linux fsid values to aio_statvfs docs.
        - work around a bug in btrfs' FIEMAP ioctl implementation.
        - work around AIX bug: statvfs.f_fsid is a struct, not unsigned long
          as per unix spec.

4.16  Tue Aug 14 05:39:03 CEST 2012
	- aio_statvfs was wromgly marked for wd emulation, causing
          it to malfunction for paths.
        - fix a crash in aio_fiemap, when used on ranges without any
        - work around linux kernel bug (at least in 3.2): kernel might
          trash fiemap input arguments.
        - work around linux kernel bug (at least in 3.2): kernel does not
          set FIEMAP_EXTENT_LAST on last segment.
        - work around linux kernel bug (at least in 3.2): kernel silently
          truncates segment count if a file.
	- make fh argument of IO::AIO::mmap optional, also add mmap/munmap
          to quick overview.
        - splice can corrupt data.
        - (libeio) remove pread/pwrite emulation.
        - do not grow mmaped scalars in aio_read.
        - add FALLOC_FL_PUNCH_HOLE and document fallocate.
        - provide pread/pwrite for win32, making it link again on native win32.

4.15  Tue Apr 10 06:59:00 CEST 2012
	- always include linux/types.h for fiemap, for compatibility to
          ancient systems (Paul Howarth).
        - experimental support for IO::AIO::splice and ::tee (no aio_...).
        - provide SEEK_HOLE and SEEK_DATA, if available.
        - work around (again!) an immensely stupid bug in RHEL, defining
          autoconf macros in linux system headers (analysed by Paul Howarth).

4.14 Sat Apr  7 02:45:18 CEST 2012
	- fix stat structure usage on windows, which caused bogus stat results.
        - (libeio) make readahead emulation behave more like actual readahead by never failing.
        - new request aio_seek.
        - new request aio_fiemap.
        - autogenerate the #ifdef/#define 0 blocks for symbols we export.

4.12 Fri Dec 30 08:51:25 CET 2011
	- realpath would return a random value if the name was too long,
          instead of -1.
        - port to c89.

4.11 Mon Oct 10 00:24:11 CEST 2011
	- libeio didn't compile on !linux (Paul Howarth).

4.1  Sun Oct  9 10:24:11 CEST 2011
        - IO::AIO did access uninitialised memory on unsuccessful stats.
	- (libeio) added syncfs syscall wrapper.
        - (libeio) set thread name on linux (ps -L/Hcx, top, gdb).
        - (libeio) support multiple indepenent working directories.
        - applied speling corrections by Nicholas Bamber.
        - tune treescan #threads and #outstanding requests a bit.
        - reduce the number of file descriptors in use at any one time
          in treescan, to avoid running out of them (and using too much ram).
        - take advantage of working directoriy abstractions
          in aio_scandir and treescan.
        - reduce compiled size by ~10% by not inlining some key functionality.
        - added --progress switch to treescan.

4.0   Mon Jul 18 05:01:10 CEST 2011
	- INCOMPATIBLE CHANGE: fork is no longer supported (indeed, it never was),
          see FORK BEHAVIOUR in manpage for details.
	- passes testsuite on win32 now and may actually work
          (activestate 5.10.1 / MSVC6, YMMV).
	- (libeio) fix a deadlock where a wakeup signal could be missed when
          a timeout occured at the same time.
	- (libeio) added realpath.
        - (libeio) added fallocate.
	- (libeio) disabling sendfile on darwin unfortunately broke the emulation.
        - (libeio) do not acquire any locks when forking.
        - (libeio) use fewer time() syscalls when waiting for new requests.

3.93  Wed Jun 29 23:44:18 CEST 2011

3.92  Wed Jun 29 14:45:41 CEST 2011
	- ecb.h was missing.

3.91  Wed Jun 29 13:24:42 CEST 2011
        - (libeio) work around a Linux (and likely FreeBSD and other
          kernels) bug where sendfile would not transfer all the requested
          bytes on large transfers, using a heuristic.
        - buggy sendfile caused aio_move/copy to sometimes fail for big
          files (fortunately it checks that the whole file has been
        - use libecb for higher performance and higher portability.
        - (libeio) disable sendfile on darwin, it's too broken.
        - disable fork tests on !linux, as only linux supports mixing
          pthread and fork in perl.
        - document the fact that fork doesn't work anymore when using
          this module, on anything !GNU/Linux.
        - increase timeout in t/04_fork.t, as too many CPAN-tester setups
          run on a 0.1MHz cpu. Or so.

3.9  Fri May 27 02:43:47 CEST 2011
        - (libeio) fix memory corruption in aio_readdirx for the flags
        - add lots of newer POSIX and GNU/Linux-specific open

3.8  Sun Mar 27 12:25:33 CEST 2011
	- use nonstandard but maybe-working-on-bsd fork technique.
	- support a max_idle value of 0.
	- support setting of idle timeout value (IO::AIO::idle_timeout).

3.72 Fri Feb 11 04:25:38 CET 2011
	- use _POSIX_MEMLOCK_RANGE to detect mlock/munlock.
        - aio_mknod always used a dev_t value of 0.
        - new treescan option: --grep.
        - add more S_IF macros, and major/minor/makedev "macros".

3.71 Thu Dec 30 08:18:46 CET 2010
	- the numerical result value passed to callbacks did not stringify
          correctly, due to internal reuse and failure to reset the sv flags.
	- actually test for posix_[mf]advise, as at least uClibc defines
          _POSIX_ADVISORY_INFO without actually having any of the required
          funcitonality. ugh.

3.7  Mon Nov  1 23:00:34 CET 2010
        - implement/add madvise, mmap, munmap, aio_mlockall, munlockall,
          aio_mlock, munlock, msync and mtouch to @EXPORT_OK.
        - document the sad state of affairs w.r.t. pthread on many bsds.
	- do not enable mmap on systems without _POSIX_MAPPED_FILES
          (openbsd 4.8).
        - do not leak memory in IO::AIO::mmap when the scalar already
          had string-data.
	- add O_RDWR, O_APPEND and O_EXCL symbols and semi-document
        - cache the result IV, for a minor speedup in the common case.
        - croak when an mmapped-scalar changes location, to detect
          user-errors better.
        - fix aio_readlink prototype.

3.65 Wed Mar 31 02:45:05 CEST 2010
	- actually use PATH_MAX instead of NAME_MAX for readlink, as to not
          cut off long pathnames in aio_readlink (based on patch by
          Rasmus Andersson).
	- a double fork partially killed the event pipe (great testcase
          by dormando). affects IO::AIO, BDB and Async::Interrupt.
        - suck steve's dick and rename our symbols to avoid colliding
          with nonstandard identifier spam on the broken os x pseudo-os.
          affects IO::AIO and BDB.

3.6  Mon Jan 11 00:43:39 CET 2010
	- (libeio) more fixes for the freebsd/apple sendfile - broken by
          manpage standards, but apparently correct accoridng to actual
          kernel sources.
        - add IO::AIO::mmap/munmap support.
        - add IO::AIO::m(un)lockall support.
        - clean up manpage.

3.5  Thu Jan  7 21:25:04 CET 2010
	- (liebio) fix freebsd sendfile (Vanilla Hsu).
        - (libeio) also fix darwin sendfile that suffered from a similar bug.
        - add aio_statvfs as interface to statvfs/fstatvfs.
        - work around buggy symlink() on cygwin in the testsuite.
        - wtf. freebsd-8.0 actually passes the testsuite! I knew
          they could implement fork and semaphores one day! cheers!

3.4  Sat Jan  2 15:13:04 CET 2010
	- (libeio) max_poll_time was not properly converted to ticks.
        - clarify cancel_subs description.
        - IO::AIO::sendfile did not actually return the return value
          from the sendfile call.
        - implement aio_msync, aio_mtouch.
        - (libeio) tentatively support darwin in sendfile.

3.31 Thu Nov 12 02:14:29 CET 2009
	- fix result status documentation of aio_copy, aio_move.
        - speed up object creation considerably by avoiding
          hash lookups.

3.3  Wed Aug  5 13:52:58 CEST 2009
	- use common::sense.
        - use common schmorp.h header.
        - allow integers (file descriptors) in addition to file handles.
        - take advantage of linux' eventfd (but it seems slower on smp?).
        - use poll not select on posix platforms.

3.261 Wed Jul  1 10:11:51 CEST 2009
	- more 0S X workarounds (patch by Tokuhiro Matsuno).

3.26 Tue Jun 30 09:33:26 CEST 2009
        - 0S X of course claims to be posix 2008 but lacks posix_fadvise.
          try to work around this horribly broken OS in a somewhat hackish
          way. might help other os's too.

3.25 Sat Jun 27 05:18:26 CEST 2009
        - added IO::AIO::fadvise and IO::AIO::sendfile.
        - (libeio) replaced quicksort+insertion sort by a tuned radix
          sort + insertion sort, resulting in comparable runtime (usually
          faster) to the old version, but without any ill side effects on
          degenerated (for quicksort) data.
        - (libeio) correctly sort dirs by inodes if we have perfect type
          knowledge and DIRS_FIRST is used.
        - (libeio) internally the wrong DT_* constants were used, but no
          known system has differing EIO_DT_*/DT_* values, so not an issue.
        - removed a (harmless) assert that was left over on the code
          but should not have been.
        - use more correct types (change IO length from IV to VAL64,
          which makes a difference on systems without 64 bit perls).

3.23 Sat Jun 13 16:57:58 CEST 2009
	- fix off-by-one bug in aio_readdir that was introduced in the
          rushed 3.22 release.

3.22 Sat Jun 13 15:32:40 CEST 2009
	- speed up readdirx sort algorithm slightly.
        - bin/treescan was missing from distro tarball.

3.21 Fri Jun 12 18:45:53 CEST 2009
	- new options --dirs and --files for treescan.
        - install bin/treescan by default.
        - (libeio) aio_readdir can now be cancelled while executing.
        - fix a printf format string for 64 bit systems (could lead
          to problems on big endian 64 bit systems).
        - do not use qsort() but our own algorithm: glibc initialises
          the whole locale and I/O subsystem inside qsort, causing
          a stack overflow on 32 bit machines. The new sort uses much less
          stack and is more than twice as fast in typical situations.

3.2  Sun Jun  7 20:30:05 CEST 2009
	- (libeio) pwrite emulation was even more flawed than intended and did
          not restore the file offset.
        - add aio_readdirx, which can return inode and filetype and sort
          the names in various ways.
        - unfortunately, utime, chmod, chown on an open file that has just
          been written can easily block, which caused aio_copy to block the
          process. no more!
        - no longer rely on dst path in aio_copy when futime is available.

3.19 Tue Apr 21 22:05:21 CEST 2009
	- more perl 5.10 workarounds for aio_read and write.
        - aio_write no longer modifies the sv (if possible).
        - aio_read now works correctly with magic values.

3.18 Sun Apr 19 21:17:32 CEST 2009
	- better diagnostics when some aio_* functions get passed an illegal fh.
        - try to avoid crashes due to incompatible 5.10 API changes. grmbl.

3.17 Thu Nov 20 08:45:36 CET 2008
	- (libeio) added aio_sync_file_range (untested).
        - add aio_busy to @IO::AIO::AIO_REQ.

3.16 Wed Oct 22 18:28:01 CEST 2008
	- use SvREFCNT_inc instead of SvREFCNT_inc_NN in a non-speed critical
          part to improve portability to perl 5.8 (reported by szymon).

3.15 Mon Oct 13 00:39:55 CEST 2008
	- automatic removal of feeders was broken.
	- (libeio) use a more robust method to detect whether a feeder
          has added something to the group or not.

3.1  Thu Oct  2 13:34:40 CEST 2008
	- pre-deref the passed callback object, for increased speed
          and decreased memory usage.
	- call on_next_submit callback even for aio_group - impact unknown,
          but seems more correct.
        - $req->cb now returns the original callback.
        - (libeio) pass EIO_GROUP/aio_group requests through the queue without
          requiring a thread switch.
        - (libeio) status code of aio_futime and aio_utime was always passed 0.
        - do some other ยต-optimisations.

3.07 Sat Aug  2 16:06:13 CEST 2008
	- do not include LIBS in autoconf tests.

3.06 Tue Jul 15 12:41:32 CEST 2008
	- move preadwritelock definition before it's first reference,
          to make it compile again on broken platforms (they still exist)
          or badly cofngiured perls (redhat...), reported by Rob Bloodgood.

3.05 Thu Jun 19 23:23:52 CEST 2008
	- work around perl overriding readdir etc. with thread-unsafe
          (sic!) versions.

3.04 Wed Jun 18 01:35:38 CEST 2008
	- (libeio) fix eio_mknod, which confused it's arguments.
	- (libeio) do not use readdir_r, as Ulrich Drepper pointed out that this
          is stupid.
        - (libeio) fix eio__readahead prototype, patch by Jost Krieger.
        - (libeio) fix a bug that could potentially cause IO::AIO
          not to get initialised properly.

3.03 Thu May 29 05:33:30 CEST 2008
	- (libeio) correctly call pthread_attr_destroy ().
        - (libeio) work around broken bsd headers once more.
        - reduce shared library size again by not including wrappers.
        - max_outstanding could cause poll to enter a busy-waiting loop.
        - document the new IO::AIO::poll_cb result value.

3.02 Mon May 12 02:32:02 CEST 2008
	- fix a memory leak on aio_readlink.
        - bring back working fchmod.
        - nop and busy now set result to 0.
        - set errno to ENOMEM when allocation fails.

3.01 Sun May 11 03:07:03 CEST 2008
	- (libeio) make it compile on systems without readahead or readdir_r.
        - (libeio) improve configure check for readahead availability.
        - do not try to link against -lrt.
	- use a separate configure script for IO::AIO (not the libeio one).

3.0  Sun May 11 00:57:14 CEST 2008
	- added bin/treescan to the distribution.
        - switched to using libeio.
          - remove signal functionality, it is not worth the effort.
          - max_outstanding no longer returns the previous number of requests.
          - poll_cb no longer returns number of requests.

2.62 Sat Apr 26 13:59:33 CEST 2008
	- port to solaris perls configured for old posix
          (analysed by Jost Krieger).
        - keep a reference to the perl filehandle object in aio_close,
          so it doesn't get closed prematurely, leading to ugly races.

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
          (suggested by ... unreachable).
        - avoid installing

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

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

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

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.

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