[ViewVC] Diff of: cvs/libeio/eio.pod

Comparing libeio/eio.pod (file contents):
Revision 1.14 by root, Tue Jul 5 14:02:15 2011 UTC vs.
Revision 1.26 by root, Mon Jul 18 02:59:58 2011 UTC

…		…
45	Unlike the name component C<stamp> might indicate, it is also used for	45	Unlike the name component C<stamp> might indicate, it is also used for
46	time differences throughout libeio.	46	time differences throughout libeio.
47		47
48	=head2 FORK SUPPORT	48	=head2 FORK SUPPORT
49		49
50	Calling C<fork ()> is fully supported by this module. It is implemented in these steps:	50	Usage of pthreads in a program changes the semantics of fork
		51	considerably. Specifically, only async-safe functions can be called after
		52	fork. Libeio uses pthreads, so this applies, and makes using fork hard for
		53	anything but relatively fork + exec uses.
51		54
52	1. wait till all requests in "execute" state have been handled	55	This library only works in the process that initialised it: Forking is
53	(basically requests that are already handed over to the kernel).	56	fully supported, but using libeio in any other process than the one that
54	2. fork	57	called C<eio_init> is not.
55	3. in the parent, continue business as usual, done
56	4. in the child, destroy all ready and pending requests and free the
57	memory used by the worker threads. This gives you a fully empty
58	libeio queue.
59		58
60	Note, however, since libeio does use threads, thr above guarantee doesn't	59	You might get around by not I<using> libeio before (or after) forking in
61	cover your libc, for example, malloc and other libc functions are not	60	the parent, and using it in the child afterwards. You could also try to
62	fork-safe, so there is very little you can do after a fork, and in fatc,	61	call the L<eio_init> function again in the child, which will brutally
63	the above might crash, and thus change.	62	reinitialise all data structures, which isn't POSIX conformant, but
		63	typically works.
		64
		65	Otherwise, the only recommendation you should follow is: treat fork code
		66	the same way you treat signal handlers, and only ever call C<eio_init> in
		67	the process that uses it, and only once ever.
64		68
65	=head1 INITIALISATION/INTEGRATION	69	=head1 INITIALISATION/INTEGRATION
66		70
67	Before you can call any eio functions you first have to initialise the	71	Before you can call any eio functions you first have to initialise the
68	library. The library integrates into any event loop, but can also be used	72	library. The library integrates into any event loop, but can also be used
…		…
77	This function initialises the library. On success it returns C<0>, on	81	This function initialises the library. On success it returns C<0>, on
78	failure it returns C<-1> and sets C<errno> appropriately.	82	failure it returns C<-1> and sets C<errno> appropriately.
79		83
80	It accepts two function pointers specifying callbacks as argument, both of	84	It accepts two function pointers specifying callbacks as argument, both of
81	which can be C<0>, in which case the callback isn't called.	85	which can be C<0>, in which case the callback isn't called.
		86
		87	There is currently no way to change these callbacks later, or to
		88	"uninitialise" the library again.
82		89
83	=item want_poll callback	90	=item want_poll callback
84		91
85	The C<want_poll> callback is invoked whenever libeio wants attention (i.e.	92	The C<want_poll> callback is invoked whenever libeio wants attention (i.e.
86	it wants to be polled by calling C<eio_poll>). It is "edge-triggered",	93	it wants to be polled by calling C<eio_poll>). It is "edge-triggered",
…		…
124	=back	131	=back
125		132
126	For libev, you would typically use an C<ev_async> watcher: the	133	For libev, you would typically use an C<ev_async> watcher: the
127	C<want_poll> callback would invoke C<ev_async_send> to wake up the event	134	C<want_poll> callback would invoke C<ev_async_send> to wake up the event
128	loop. Inside the callback set for the watcher, one would call C<eio_poll	135	loop. Inside the callback set for the watcher, one would call C<eio_poll
129	()> (followed by C<ev_async_send> again if C<eio_poll> indicates that not	136	()>.
130	all requests have been handled yet). The race is taken care of because	137
131	libev resets/rearms the async watcher before calling your callback,	138	If C<eio_poll ()> is configured to not handle all results in one go
132	and therefore, before calling C<eio_poll>. This might result in (some)	139	(i.e. it returns C<-1>) then you should start an idle watcher that calls
133	spurious wake-ups, but is generally harmless.	140	C<eio_poll> until it returns something C<!= -1>.
		141
		142	A full-featured connector between libeio and libev would look as follows
		143	(if C<eio_poll> is handling all requests, it can of course be simplified a
		144	lot by removing the idle watcher logic):
		145
		146	static struct ev_loop *loop;
		147	static ev_idle repeat_watcher;
		148	static ev_async ready_watcher;
		149
		150	/* idle watcher callback, only used when eio_poll */
		151	/* didn't handle all results in one call */
		152	static void
		153	repeat (EV_P_ ev_idle *w, int revents)
		154	{
		155	if (eio_poll () != -1)
		156	ev_idle_stop (EV_A_ w);
		157	}
		158
		159	/* eio has some results, process them */
		160	static void
		161	ready (EV_P_ ev_async *w, int revents)
		162	{
		163	if (eio_poll () == -1)
		164	ev_idle_start (EV_A_ &repeat_watcher);
		165	}
		166
		167	/* wake up the event loop */
		168	static void
		169	want_poll (void)
		170	{
		171	ev_async_send (loop, &ready_watcher)
		172	}
		173
		174	void
		175	my_init_eio ()
		176	{
		177	loop = EV_DEFAULT;
		178
		179	ev_idle_init (&repeat_watcher, repeat);
		180	ev_async_init (&ready_watcher, ready);
		181	ev_async_start (loop &watcher);
		182
		183	eio_init (want_poll, 0);
		184	}
134		185
135	For most other event loops, you would typically use a pipe - the event	186	For most other event loops, you would typically use a pipe - the event
136	loop should be told to wait for read readiness on the read end. In	187	loop should be told to wait for read readiness on the read end. In
137	C<want_poll> you would write a single byte, in C<done_poll> you would try	188	C<want_poll> you would write a single byte, in C<done_poll> you would try
138	to read that byte, and in the callback for the read end, you would call	189	to read that byte, and in the callback for the read end, you would call
139	C<eio_poll>. The race is avoided here because the event loop should invoke	190	C<eio_poll>.
140	your callback again and again until the byte has been read (as the pipe	191
141	read callback does not read it, only C<done_poll>).	192	You don't have to take special care in the case C<eio_poll> doesn't handle
		193	all requests, as the done callback will not be invoked, so the event loop
		194	will still signal readiness for the pipe until I<all> results have been
		195	processed.
142		196
143		197
144	=head1 HIGH LEVEL REQUEST API	198	=head1 HIGH LEVEL REQUEST API
145		199
146	Libeio has both a high-level API, which consists of calling a request	200	Libeio has both a high-level API, which consists of calling a request
…		…
213	}	267	}
214		268
215	/* the first three arguments are passed to open(2) */	269	/* the first three arguments are passed to open(2) */
216	/* the remaining are priority, callback and data */	270	/* the remaining are priority, callback and data */
217	if (!eio_open ("/etc/passwd", O_RDONLY, 0, 0, file_open_done, 0))	271	if (!eio_open ("/etc/passwd", O_RDONLY, 0, 0, file_open_done, 0))
218	abort (); /* something ent wrong, we will all die!!! */	272	abort (); /* something went wrong, we will all die!!! */
219		273
220	Note that you additionally need to call C<eio_poll> when the C<want_cb>	274	Note that you additionally need to call C<eio_poll> when the C<want_cb>
221	indicates that requests are ready to be processed.	275	indicates that requests are ready to be processed.
		276
		277	=head2 CANCELLING REQUESTS
		278
		279	Sometimes the need for a request goes away before the request is
		280	finished. In that case, one can cancel the request by a call to
		281	C<eio_cancel>:
		282
		283	=over 4
		284
		285	=item eio_cancel (eio_req *req)
		286
		287	Cancel the request (and all its subrequests). If the request is currently
		288	executing it might still continue to execute, and in other cases it might
		289	still take a while till the request is cancelled.
		290
		291	Even if cancelled, the finish callback will still be invoked - the
		292	callbacks of all cancellable requests need to check whether the request
		293	has been cancelled by calling C<EIO_CANCELLED (req)>:
		294
		295	static int
		296	my_eio_cb (eio_req *req)
		297	{
		298	if (EIO_CANCELLED (req))
		299	return 0;
		300	}
		301
		302	In addition, cancelled requests will I<either> have C<< req->result >>
		303	set to C<-1> and C<errno> to C<ECANCELED>, or I<otherwise> they were
		304	successfully executed, despite being cancelled (e.g. when they have
		305	already been executed at the time they were cancelled).
		306
		307	C<EIO_CANCELLED> is still true for requests that have successfully
		308	executed, as long as C<eio_cancel> was called on them at some point.
		309
		310	=back
222		311
223	=head2 AVAILABLE REQUESTS	312	=head2 AVAILABLE REQUESTS
224		313
225	The following request functions are available. I<All> of them return the	314	The following request functions are available. I<All> of them return the
226	C<eio_req *> on success and C<0> on failure, and I<all> of them have the	315	C<eio_req *> on success and C<0> on failure, and I<all> of them have the
…		…
322	free (target);	411	free (target);
323	}	412	}
324		413
325	=item eio_realpath (const char path, int pri, eio_cb cb, void data)	414	=item eio_realpath (const char path, int pri, eio_cb cb, void data)
326		415
327	Similar to the realpath libc function, but unlike that one, result is	416	Similar to the realpath libc function, but unlike that one, C<<
328	C<-1> on failure and the length of the returned path in C<ptr2> (which is	417	req->result >> is C<-1> on failure. On success, the result is the length
329	not 0-terminated) - this is similar to readlink.	418	of the returned path in C<ptr2> (which is I<NOT> 0-terminated) - this is
		419	similar to readlink.
330		420
331	=item eio_stat (const char path, int pri, eio_cb cb, void data)	421	=item eio_stat (const char path, int pri, eio_cb cb, void data)
332		422
333	=item eio_lstat (const char path, int pri, eio_cb cb, void data)	423	=item eio_lstat (const char path, int pri, eio_cb cb, void data)
334		424
335	=item eio_fstat (int fd, int pri, eio_cb cb, void *data)	425	=item eio_fstat (int fd, int pri, eio_cb cb, void *data)
336		426
337	Stats a file - if C<< req->result >> indicates success, then you can	427	Stats a file - if C<< req->result >> indicates success, then you can
338	access the C<struct stat>-like structure via C<< req->ptr2 >>:	428	access the C<struct stat>-like structure via C<< req->ptr2 >>:
339		429
340	EIO_STRUCT_STAT statdata = (EIO_STRUCT_STAT )req->ptr2;	430	EIO_STRUCT_STAT statdata = (EIO_STRUCT_STAT )req->ptr2;
341		431
342	=item eio_statvfs (const char path, int pri, eio_cb cb, void data)	432	=item eio_statvfs (const char path, int pri, eio_cb cb, void data)
343		433
344	=item eio_fstatvfs (int fd, int pri, eio_cb cb, void *data)	434	=item eio_fstatvfs (int fd, int pri, eio_cb cb, void *data)
345		435
346	Stats a filesystem - if C<< req->result >> indicates success, then you can	436	Stats a filesystem - if C<< req->result >> indicates success, then you can
347	access the C<struct statvfs>-like structure via C<< req->ptr2 >>:	437	access the C<struct statvfs>-like structure via C<< req->ptr2 >>:
348		438
349	EIO_STRUCT_STATVFS statdata = (EIO_STRUCT_STATVFS )req->ptr2;	439	EIO_STRUCT_STATVFS statdata = (EIO_STRUCT_STATVFS )req->ptr2;
350		440
351	=back	441	=back
352		442
353	=head3 READING DIRECTORIES	443	=head3 READING DIRECTORIES
354		444
355	Reading directories sounds simple, but can be rather demanding, especially	445	Reading directories sounds simple, but can be rather demanding, especially
356	if you want to do stuff such as traversing a diretcory hierarchy or	446	if you want to do stuff such as traversing a directory hierarchy or
357	processing all files in a directory. Libeio can assist thess complex tasks	447	processing all files in a directory. Libeio can assist these complex tasks
358	with it's C<eio_readdir> call.	448	with it's C<eio_readdir> call.
359		449
360	=over 4	450	=over 4
361		451
362	=item eio_readdir (const char path, int flags, int pri, eio_cb cb, void data)	452	=item eio_readdir (const char path, int flags, int pri, eio_cb cb, void data)
…		…
394		484
395	If this flag is specified, then, in addition to the names in C<ptr2>,	485	If this flag is specified, then, in addition to the names in C<ptr2>,
396	also an array of C<struct eio_dirent> is returned, in C<ptr1>. A C<struct	486	also an array of C<struct eio_dirent> is returned, in C<ptr1>. A C<struct
397	eio_dirent> looks like this:	487	eio_dirent> looks like this:
398		488
399	struct eio_dirent	489	struct eio_dirent
400	{	490	{
401	int nameofs; /* offset of null-terminated name string in (char )req->ptr2 /	491	int nameofs; /* offset of null-terminated name string in (char )req->ptr2 /
402	unsigned short namelen; /* size of filename without trailing 0 */	492	unsigned short namelen; /* size of filename without trailing 0 */
403	unsigned char type; /* one of EIO_DT_* */	493	unsigned char type; /* one of EIO_DT_* */
404	signed char score; /* internal use */	494	signed char score; /* internal use */
405	ino_t inode; /* the inode number, if available, otherwise unspecified */	495	ino_t inode; /* the inode number, if available, otherwise unspecified */
406	};	496	};
407		497
408	The only members you normally would access are C<nameofs>, which is the	498	The only members you normally would access are C<nameofs>, which is the
409	byte-offset from C<ptr2> to the start of the name, C<namelen> and C<type>.	499	byte-offset from C<ptr2> to the start of the name, C<namelen> and C<type>.
410		500
411	C<type> can be one of:	501	C<type> can be one of:
…		…
454	When this flag is specified, then the names will be returned in an order	544	When this flag is specified, then the names will be returned in an order
455	suitable for stat()'ing each one. That is, when you plan to stat()	545	suitable for stat()'ing each one. That is, when you plan to stat()
456	all files in the given directory, then the returned order will likely	546	all files in the given directory, then the returned order will likely
457	be fastest.	547	be fastest.
458		548
459	If both this flag and C<EIO_READDIR_DIRS_FIRST> are specified, then	549	If both this flag and C<EIO_READDIR_DIRS_FIRST> are specified, then the
460	the likely dirs come first, resulting in a less optimal stat order.	550	likely directories come first, resulting in a less optimal stat order.
461		551
462	=item EIO_READDIR_FOUND_UNKNOWN	552	=item EIO_READDIR_FOUND_UNKNOWN
463		553
464	This flag should not be specified when calling C<eio_readdir>. Instead,	554	This flag should not be specified when calling C<eio_readdir>. Instead,
465	it is being set by C<eio_readdir> (you can access the C<flags> via C<<	555	it is being set by C<eio_readdir> (you can access the C<flags> via C<<
466	req->int1 >>, when any of the C<type>'s found were C<EIO_DT_UNKNOWN>. The	556	req->int1 >>, when any of the C<type>'s found were C<EIO_DT_UNKNOWN>. The
467	absense of this flag therefore indicates that all C<type>'s are known,	557	absence of this flag therefore indicates that all C<type>'s are known,
468	which can be used to speed up some algorithms.	558	which can be used to speed up some algorithms.
469		559
470	A typical use case would be to identify all subdirectories within a	560	A typical use case would be to identify all subdirectories within a
471	directory - you would ask C<eio_readdir> for C<EIO_READDIR_DIRS_FIRST>. If	561	directory - you would ask C<eio_readdir> for C<EIO_READDIR_DIRS_FIRST>. If
472	then this flag is I<NOT> set, then all the entries at the beginning of the	562	then this flag is I<NOT> set, then all the entries at the beginning of the
…		…
510	as calling C<fdatasync>.	600	as calling C<fdatasync>.
511		601
512	Flags can be any combination of C<EIO_SYNC_FILE_RANGE_WAIT_BEFORE>,	602	Flags can be any combination of C<EIO_SYNC_FILE_RANGE_WAIT_BEFORE>,
513	C<EIO_SYNC_FILE_RANGE_WRITE> and C<EIO_SYNC_FILE_RANGE_WAIT_AFTER>.	603	C<EIO_SYNC_FILE_RANGE_WRITE> and C<EIO_SYNC_FILE_RANGE_WAIT_AFTER>.
514		604
		605	=item eio_fallocate (int fd, int mode, off_t offset, off_t len, int pri, eio_cb cb, void *data)
		606
		607	Calls C<fallocate> (note: I<NOT> C<posix_fallocate>!). If the syscall is
		608	missing, then it returns failure and sets C<errno> to C<ENOSYS>.
		609
		610	The C<mode> argument can be C<0> (for behaviour similar to
		611	C<posix_fallocate>), or C<EIO_FALLOC_FL_KEEP_SIZE>, which keeps the size
		612	of the file unchanged (but still preallocates space beyond end of file).
		613
515	=back	614	=back
516		615
517	=head3 LIBEIO-SPECIFIC REQUESTS	616	=head3 LIBEIO-SPECIFIC REQUESTS
518		617
519	These requests are specific to libeio and do not correspond to any OS call.	618	These requests are specific to libeio and do not correspond to any OS call.
…		…
560		659
561	eio_custom (my_open, 0, my_open_done, "/etc/passwd");	660	eio_custom (my_open, 0, my_open_done, "/etc/passwd");
562		661
563	=item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data)	662	=item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data)
564		663
565	This is a a request that takes C<delay> seconds to execute, but otherwise	664	This is a request that takes C<delay> seconds to execute, but otherwise
566	does nothing - it simply puts one of the worker threads to sleep for this	665	does nothing - it simply puts one of the worker threads to sleep for this
567	long.	666	long.
568		667
569	This request can be used to artificially increase load, e.g. for debugging	668	This request can be used to artificially increase load, e.g. for debugging
570	or benchmarking reasons.	669	or benchmarking reasons.
…		…
586	There are two primary use cases for this: a) bundle many requests into a	685	There are two primary use cases for this: a) bundle many requests into a
587	single, composite, request with a definite callback and the ability to	686	single, composite, request with a definite callback and the ability to
588	cancel the whole request with its subrequests and b) limiting the number	687	cancel the whole request with its subrequests and b) limiting the number
589	of "active" requests.	688	of "active" requests.
590		689
591	Further below you will find more dicussion of these topics - first follows	690	Further below you will find more discussion of these topics - first
592	the reference section detailing the request generator and other methods.	691	follows the reference section detailing the request generator and other
		692	methods.
593		693
594	=over 4	694	=over 4
595		695
596	=item eio_grp (eio_cb cb, void *data)	696	=item eio_req grp = eio_grp (eio_cb cb, void data)
597		697
598	Creates and submits a group request.	698	Creates, submits and returns a group request. Note that it doesn't have a
		699	priority, unlike all other requests.
599		700
600	=back	701	=item eio_grp_add (eio_req grp, eio_req req)
601		702
		703	Adds a request to the request group.
		704
		705	=item eio_grp_cancel (eio_req *grp)
		706
		707	Cancels all requests I<in> the group, but I<not> the group request
		708	itself. You can cancel the group request I<and> all subrequests via a
		709	normal C<eio_cancel> call.
		710
		711	=back
		712
		713	=head4 GROUP REQUEST LIFETIME
		714
		715	Left alone, a group request will instantly move to the pending state and
		716	will be finished at the next call of C<eio_poll>.
		717
		718	The usefulness stems from the fact that, if a subrequest is added to a
		719	group I<before> a call to C<eio_poll>, via C<eio_grp_add>, then the group
		720	will not finish until all the subrequests have finished.
		721
		722	So the usage cycle of a group request is like this: after it is created,
		723	you normally instantly add a subrequest. If none is added, the group
		724	request will finish on it's own. As long as subrequests are added before
		725	the group request is finished it will be kept from finishing, that is the
		726	callbacks of any subrequests can, in turn, add more requests to the group,
		727	and as long as any requests are active, the group request itself will not
		728	finish.
		729
		730	=head4 CREATING COMPOSITE REQUESTS
		731
		732	Imagine you wanted to create an C<eio_load> request that opens a file,
		733	reads it and closes it. This means it has to execute at least three eio
		734	requests, but for various reasons it might be nice if that request looked
		735	like any other eio request.
		736
		737	This can be done with groups:
		738
		739	=over 4
		740
		741	=item 1) create the request object
		742
		743	Create a group that contains all further requests. This is the request you
		744	can return as "the load request".
		745
		746	=item 2) open the file, maybe
		747
		748	Next, open the file with C<eio_open> and add the request to the group
		749	request and you are finished setting up the request.
		750
		751	If, for some reason, you cannot C<eio_open> (path is a null ptr?) you
		752	can set C<< grp->result >> to C<-1> to signal an error and let the group
		753	request finish on its own.
		754
		755	=item 3) open callback adds more requests
		756
		757	In the open callback, if the open was not successful, copy C<<
		758	req->errorno >> to C<< grp->errorno >> and set C<< grp->errorno >> to
		759	C<-1> to signal an error.
		760
		761	Otherwise, malloc some memory or so and issue a read request, adding the
		762	read request to the group.
		763
		764	=item 4) continue issuing requests till finished
		765
		766	In the real callback, check for errors and possibly continue with
		767	C<eio_close> or any other eio request in the same way.
		768
		769	As soon as no new requests are added the group request will finish. Make
		770	sure you I<always> set C<< grp->result >> to some sensible value.
		771
		772	=back
		773
		774	=head4 REQUEST LIMITING
602		775
603		776
604	#TODO	777	#TODO
605		778
606	/*****************************************************************************/
607	/* groups */
608
609	eio_req eio_grp (eio_cb cb, void data);
610	void eio_grp_feed (eio_req grp, void (feed)(eio_req *req), int limit);
611	void eio_grp_limit (eio_req *grp, int limit);	779	void eio_grp_limit (eio_req *grp, int limit);
612	void eio_grp_add (eio_req grp, eio_req req);
613	void eio_grp_cancel (eio_req grp); / cancels all sub requests but not the group */
614		780
615		781
616	=back	782	=back
617		783
618		784
…		…
624	=head1 ANATOMY AND LIFETIME OF AN EIO REQUEST	790	=head1 ANATOMY AND LIFETIME OF AN EIO REQUEST
625		791
626	A request is represented by a structure of type C<eio_req>. To initialise	792	A request is represented by a structure of type C<eio_req>. To initialise
627	it, clear it to all zero bytes:	793	it, clear it to all zero bytes:
628		794
629	eio_req req;	795	eio_req req;
630		796
631	memset (&req, 0, sizeof (req));	797	memset (&req, 0, sizeof (req));
632		798
633	A more common way to initialise a new C<eio_req> is to use C<calloc>:	799	A more common way to initialise a new C<eio_req> is to use C<calloc>:
634		800
635	eio_req req = calloc (1, sizeof (req));	801	eio_req req = calloc (1, sizeof (req));
636		802
637	In either case, libeio neither allocates, initialises or frees the	803	In either case, libeio neither allocates, initialises or frees the
638	C<eio_req> structure for you - it merely uses it.	804	C<eio_req> structure for you - it merely uses it.
639		805
640	zero	806	zero
…		…
658	for example, in interactive programs, you might want to limit this time to	824	for example, in interactive programs, you might want to limit this time to
659	C<0.01> seconds or so.	825	C<0.01> seconds or so.
660		826
661	Note that:	827	Note that:
662		828
		829	=over 4
		830
663	a) libeio doesn't know how long your request callbacks take, so the time	831	=item a) libeio doesn't know how long your request callbacks take, so the
664	spent in C<eio_poll> is up to one callback invocation longer then this	832	time spent in C<eio_poll> is up to one callback invocation longer then
665	interval.	833	this interval.
666		834
667	b) this is implemented by calling C<gettimeofday> after each request,	835	=item b) this is implemented by calling C<gettimeofday> after each
668	which can be costly.	836	request, which can be costly.
669		837
670	c) at least one request will be handled.	838	=item c) at least one request will be handled.
		839
		840	=back
671		841
672	=item eio_set_max_poll_reqs (unsigned int nreqs)	842	=item eio_set_max_poll_reqs (unsigned int nreqs)
673		843
674	When C<nreqs> is non-zero, then C<eio_poll> will not handle more than	844	When C<nreqs> is non-zero, then C<eio_poll> will not handle more than
675	C<nreqs> requests per invocation. This is a less costly way to limit the	845	C<nreqs> requests per invocation. This is a less costly way to limit the
…		…
745	This symbol governs the stack size for each eio thread. Libeio itself	915	This symbol governs the stack size for each eio thread. Libeio itself
746	was written to use very little stackspace, but when using C<EIO_CUSTOM>	916	was written to use very little stackspace, but when using C<EIO_CUSTOM>
747	requests, you might want to increase this.	917	requests, you might want to increase this.
748		918
749	If this symbol is undefined (the default) then libeio will use its default	919	If this symbol is undefined (the default) then libeio will use its default
750	stack size (C<sizeof (long) * 4096> currently). If it is defined, but	920	stack size (C<sizeof (void ) 4096> currently). If it is defined, but
751	C<0>, then the default operating system stack size will be used. In all	921	C<0>, then the default operating system stack size will be used. In all
752	other cases, the value must be an expression that evaluates to the desired	922	other cases, the value must be an expression that evaluates to the desired
753	stack size.	923	stack size.
754		924
755	=back	925	=back

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Comparing libeio/eio.pod (file contents): Revision 1.14 by root, Tue Jul 5 14:02:15 2011 UTC vs. Revision 1.26 by root, Mon Jul 18 02:59:58 2011 UTC

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Comparing libeio/eio.pod (file contents):
Revision 1.14 by root, Tue Jul 5 14:02:15 2011 UTC vs.
Revision 1.26 by root, Mon Jul 18 02:59:58 2011 UTC