ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/Coro/README
(Generate patch)

Comparing Coro/README (file contents):
Revision 1.3 by root, Mon Nov 6 19:56:26 2006 UTC vs.
Revision 1.19 by root, Mon Nov 24 07:55:28 2008 UTC

1NAME 1NAME
2 Coro - coroutine process abstraction 2 Coro - the only real threads in perl
3 3
4SYNOPSIS 4SYNOPSIS
5 use Coro; 5 use Coro;
6 6
7 async { 7 async {
8 # some asynchronous thread of execution 8 # some asynchronous thread of execution
9 print "2\n";
10 cede; # yield back to main
11 print "4\n";
9 }; 12 };
10 13 print "1\n";
11 # alternatively create an async process like this: 14 cede; # yield to coroutine
12 15 print "3\n";
13 sub some_func : Coro { 16 cede; # and again
14 # some more async code
15 } 17
16 18 # use locking
17 cede; 19 use Coro::Semaphore;
20 my $lock = new Coro::Semaphore;
21 my $locked;
22
23 $lock->down;
24 $locked = 1;
25 $lock->up;
18 26
19DESCRIPTION 27DESCRIPTION
20 This module collection manages coroutines. Coroutines are similar to 28 For a tutorial-style introduction, please read the Coro::Intro manpage.
21 threads but don't run in parallel. 29 This manpage mainly contains reference information.
22 30
31 This module collection manages continuations in general, most often in
32 the form of cooperative threads (also called coroutines in the
33 documentation). They are similar to kernel threads but don't (in
34 general) run in parallel at the same time even on SMP machines. The
35 specific flavor of thread offered by this module also guarantees you
36 that it will not switch between threads unless necessary, at
37 easily-identified points in your program, so locking and parallel access
38 are rarely an issue, making thread programming much safer and easier
39 than using other thread models.
40
41 Unlike the so-called "Perl threads" (which are not actually real threads
42 but only the windows process emulation ported to unix), Coro provides a
43 full shared address space, which makes communication between threads
44 very easy. And threads are fast, too: disabling the Windows process
45 emulation code in your perl and using Coro can easily result in a two to
46 four times speed increase for your programs.
47
48 Coro achieves that by supporting multiple running interpreters that
49 share data, which is especially useful to code pseudo-parallel processes
50 and for event-based programming, such as multiple HTTP-GET requests
51 running concurrently. See Coro::AnyEvent to learn more on how to
52 integrate Coro into an event-based environment.
53
23 In this module, coroutines are defined as "callchain + lexical variables 54 In this module, a thread is defined as "callchain + lexical variables +
24 + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own 55 @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain,
25 callchain, it's own set of lexicals and it's own set of perl's most 56 its own set of lexicals and its own set of perls most important global
26 important global variables. 57 variables (see Coro::State for more configuration and background info).
27 58
59 See also the "SEE ALSO" section at the end of this document - the Coro
60 module family is quite large.
61
62GLOBAL VARIABLES
28 $main 63 $Coro::main
29 This coroutine represents the main program. 64 This variable stores the coroutine object that represents the main
65 program. While you cna "ready" it and do most other things you can
66 do to coroutines, it is mainly useful to compare again
67 $Coro::current, to see whether you are running in the main program
68 or not.
30 69
31 $current (or as function: current) 70 $Coro::current
32 The current coroutine (the last coroutine switched to). The initial 71 The coroutine object representing the current coroutine (the last
72 coroutine that the Coro scheduler switched to). The initial value is
33 value is $main (of course). 73 $Coro::main (of course).
34 74
75 This variable is strictly *read-only*. You can take copies of the
76 value stored in it and use it as any other coroutine object, but you
77 must not otherwise modify the variable itself.
78
35 $idle 79 $Coro::idle
36 The coroutine to switch to when no other coroutine is running. The 80 This variable is mainly useful to integrate Coro into event loops.
37 default implementation prints "FATAL: deadlock detected" and exits. 81 It is usually better to rely on Coro::AnyEvent or Coro::EV, as this
82 is pretty low-level functionality.
38 83
39 STATIC METHODS 84 This variable stores either a coroutine or a callback.
40 Static methods are actually functions that operate on the current
41 process only.
42 85
86 If it is a callback, the it is called whenever the scheduler finds
87 no ready coroutines to run. The default implementation prints
88 "FATAL: deadlock detected" and exits, because the program has no
89 other way to continue.
90
91 If it is a coroutine object, then this object will be readied
92 (without invoking any ready hooks, however) when the scheduler finds
93 no other ready coroutines to run.
94
95 This hook is overwritten by modules such as "Coro::EV" and
96 "Coro::AnyEvent" to wait on an external event that hopefully wake up
97 a coroutine so the scheduler can run it.
98
99 Note that the callback *must not*, under any circumstances, block
100 the current coroutine. Normally, this is achieved by having an "idle
101 coroutine" that calls the event loop and then blocks again, and then
102 readying that coroutine in the idle handler, or by simply placing
103 the idle coroutine in this variable.
104
105 See Coro::Event or Coro::AnyEvent for examples of using this
106 technique.
107
108 Please note that if your callback recursively invokes perl (e.g. for
109 event handlers), then it must be prepared to be called recursively
110 itself.
111
112SIMPLE COROUTINE CREATION
43 async { ... } [@args...] 113 async { ... } [@args...]
44 Create a new asynchronous process and return it's process object 114 Create a new coroutine and return it's coroutine object (usually
45 (usually unused). When the sub returns the new process is 115 unused). The coroutine will be put into the ready queue, so it will
116 start running automatically on the next scheduler run.
117
118 The first argument is a codeblock/closure that should be executed in
119 the coroutine. When it returns argument returns the coroutine is
46 automatically terminated. 120 automatically terminated.
47 121
48 When the coroutine dies, the program will exit, just as in the main 122 The remaining arguments are passed as arguments to the closure.
49 program.
50 123
124 See the "Coro::State::new" constructor for info about the coroutine
125 environment in which coroutines are executed.
126
127 Calling "exit" in a coroutine will do the same as calling exit
128 outside the coroutine. Likewise, when the coroutine dies, the
129 program will exit, just as it would in the main program.
130
131 If you do not want that, you can provide a default "die" handler, or
132 simply avoid dieing (by use of "eval").
133
51 # create a new coroutine that just prints its arguments 134 Example: Create a new coroutine that just prints its arguments.
135
52 async { 136 async {
53 print "@_\n"; 137 print "@_\n";
54 } 1,2,3,4; 138 } 1,2,3,4;
55 139
140 async_pool { ... } [@args...]
141 Similar to "async", but uses a coroutine pool, so you should not
142 call terminate or join on it (although you are allowed to), and you
143 get a coroutine that might have executed other code already (which
144 can be good or bad :).
145
146 On the plus side, this function is about twice as fast as creating
147 (and destroying) a completely new coroutine, so if you need a lot of
148 generic coroutines in quick successsion, use "async_pool", not
149 "async".
150
151 The code block is executed in an "eval" context and a warning will
152 be issued in case of an exception instead of terminating the
153 program, as "async" does. As the coroutine is being reused, stuff
154 like "on_destroy" will not work in the expected way, unless you call
155 terminate or cancel, which somehow defeats the purpose of pooling
156 (but is fine in the exceptional case).
157
158 The priority will be reset to 0 after each run, tracing will be
159 disabled, the description will be reset and the default output
160 filehandle gets restored, so you can change all these. Otherwise the
161 coroutine will be re-used "as-is": most notably if you change other
162 per-coroutine global stuff such as $/ you *must needs* revert that
163 change, which is most simply done by using local as in: "local $/".
164
165 The idle pool size is limited to 8 idle coroutines (this can be
166 adjusted by changing $Coro::POOL_SIZE), but there can be as many
167 non-idle coros as required.
168
169 If you are concerned about pooled coroutines growing a lot because a
170 single "async_pool" used a lot of stackspace you can e.g.
171 "async_pool { terminate }" once per second or so to slowly replenish
172 the pool. In addition to that, when the stacks used by a handler
173 grows larger than 32kb (adjustable via $Coro::POOL_RSS) it will also
174 be destroyed.
175
176STATIC METHODS
177 Static methods are actually functions that implicitly operate on the
178 current coroutine.
179
56 schedule 180 schedule
57 Calls the scheduler. Please note that the current process will not 181 Calls the scheduler. The scheduler will find the next coroutine that
182 is to be run from the ready queue and switches to it. The next
183 coroutine to be run is simply the one with the highest priority that
184 is longest in its ready queue. If there is no coroutine ready, it
185 will clal the $Coro::idle hook.
186
187 Please note that the current coroutine will *not* be put into the
58 be put into the ready queue, so calling this function usually means 188 ready queue, so calling this function usually means you will never
59 you will never be called again. 189 be called again unless something else (e.g. an event handler) calls
190 "->ready", thus waking you up.
191
192 This makes "schedule" *the* generic method to use to block the
193 current coroutine and wait for events: first you remember the
194 current coroutine in a variable, then arrange for some callback of
195 yours to call "->ready" on that once some event happens, and last
196 you call "schedule" to put yourself to sleep. Note that a lot of
197 things can wake your coroutine up, so you need to check whether the
198 event indeed happened, e.g. by storing the status in a variable.
199
200 See HOW TO WAIT FOR A CALLBACK, below, for some ways to wait for
201 callbacks.
60 202
61 cede 203 cede
62 "Cede" to other processes. This function puts the current process 204 "Cede" to other coroutines. This function puts the current coroutine
63 into the ready queue and calls "schedule", which has the effect of 205 into the ready queue and calls "schedule", which has the effect of
64 giving up the current "timeslice" to other coroutines of the same or 206 giving up the current "timeslice" to other coroutines of the same or
65 higher priority. 207 higher priority. Once your coroutine gets its turn again it will
208 automatically be resumed.
209
210 This function is often called "yield" in other languages.
211
212 Coro::cede_notself
213 Works like cede, but is not exported by default and will cede to
214 *any* coroutine, regardless of priority. This is useful sometimes to
215 ensure progress is made.
66 216
67 terminate [arg...] 217 terminate [arg...]
68 Terminates the current process with the given status values (see 218 Terminates the current coroutine with the given status values (see
69 cancel). 219 cancel).
70 220
71 # dynamic methods 221 killall
222 Kills/terminates/cancels all coroutines except the currently running
223 one. This is useful after a fork, either in the child or the parent,
224 as usually only one of them should inherit the running coroutines.
72 225
73 PROCESS METHODS 226 Note that while this will try to free some of the main programs
227 resources, you cannot free all of them, so if a coroutine that is
228 not the main program calls this function, there will be some
229 one-time resource leak.
230
231COROUTINE OBJECT METHODS
74 These are the methods you can call on process objects. 232 These are the methods you can call on coroutine objects (or to create
233 them).
75 234
76 new Coro \&sub [, @args...] 235 new Coro \&sub [, @args...]
77 Create a new process and return it. When the sub returns the process 236 Create a new coroutine and return it. When the sub returns, the
78 automatically terminates as if "terminate" with the returned values 237 coroutine automatically terminates as if "terminate" with the
79 were called. To make the process run you must first put it into the 238 returned values were called. To make the coroutine run you must
80 ready queue by calling the ready method. 239 first put it into the ready queue by calling the ready method.
81 240
82 $process->ready 241 See "async" and "Coro::State::new" for additional info about the
83 Put the given process into the ready queue. 242 coroutine environment.
84 243
244 $success = $coroutine->ready
245 Put the given coroutine into the end of its ready queue (there is
246 one queue for each priority) and return true. If the coroutine is
247 already in the ready queue, do nothing and return false.
248
249 This ensures that the scheduler will resume this coroutine
250 automatically once all the coroutines of higher priority and all
251 coroutines of the same priority that were put into the ready queue
252 earlier have been resumed.
253
254 $is_ready = $coroutine->is_ready
255 Return whether the coroutine is currently the ready queue or not,
256
85 $process->cancel (arg...) 257 $coroutine->cancel (arg...)
86 Terminates the given process and makes it return the given arguments 258 Terminates the given coroutine and makes it return the given
87 as status (default: the empty list). 259 arguments as status (default: the empty list). Never returns if the
260 coroutine is the current coroutine.
88 261
89 $process->join 262 $coroutine->schedule_to
263 Puts the current coroutine to sleep (like "Coro::schedule"), but
264 instead of continuing with the next coro from the ready queue,
265 always switch to the given coroutine object (regardless of priority
266 etc.). The readyness state of that coroutine isn't changed.
267
268 This is an advanced method for special cases - I'd love to hear
269 about any uses for this one.
270
271 $coroutine->cede_to
272 Like "schedule_to", but puts the current coroutine into the ready
273 queue. This has the effect of temporarily switching to the given
274 coroutine, and continuing some time later.
275
276 This is an advanced method for special cases - I'd love to hear
277 about any uses for this one.
278
279 $coroutine->throw ([$scalar])
280 If $throw is specified and defined, it will be thrown as an
281 exception inside the coroutine at the next convenient point in time.
282 Otherwise clears the exception object.
283
284 Coro will check for the exception each time a schedule-like-function
285 returns, i.e. after each "schedule", "cede",
286 "Coro::Semaphore->down", "Coro::Handle->readable" and so on. Most of
287 these functions detect this case and return early in case an
288 exception is pending.
289
290 The exception object will be thrown "as is" with the specified
291 scalar in $@, i.e. if it is a string, no line number or newline will
292 be appended (unlike with "die").
293
294 This can be used as a softer means than "cancel" to ask a coroutine
295 to end itself, although there is no guarantee that the exception
296 will lead to termination, and if the exception isn't caught it might
297 well end the whole program.
298
299 You might also think of "throw" as being the moral equivalent of
300 "kill"ing a coroutine with a signal (in this case, a scalar).
301
302 $coroutine->join
90 Wait until the coroutine terminates and return any values given to 303 Wait until the coroutine terminates and return any values given to
91 the "terminate" or "cancel" functions. "join" can be called multiple 304 the "terminate" or "cancel" functions. "join" can be called
92 times from multiple processes. 305 concurrently from multiple coroutines, and all will be resumed and
306 given the status return once the $coroutine terminates.
93 307
308 $coroutine->on_destroy (\&cb)
309 Registers a callback that is called when this coroutine gets
310 destroyed, but before it is joined. The callback gets passed the
311 terminate arguments, if any, and *must not* die, under any
312 circumstances.
313
94 $oldprio = $process->prio($newprio) 314 $oldprio = $coroutine->prio ($newprio)
95 Sets (or gets, if the argument is missing) the priority of the 315 Sets (or gets, if the argument is missing) the priority of the
96 process. Higher priority processes get run before lower priority 316 coroutine. Higher priority coroutines get run before lower priority
97 processes. Priorities are small signed integers (currently -4 .. 317 coroutines. Priorities are small signed integers (currently -4 ..
98 +3), that you can refer to using PRIO_xxx constants (use the import 318 +3), that you can refer to using PRIO_xxx constants (use the import
99 tag :prio to get then): 319 tag :prio to get then):
100 320
101 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 321 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
102 3 > 1 > 0 > -1 > -3 > -4 322 3 > 1 > 0 > -1 > -3 > -4
105 current->prio(PRIO_HIGH); 325 current->prio(PRIO_HIGH);
106 326
107 The idle coroutine ($Coro::idle) always has a lower priority than 327 The idle coroutine ($Coro::idle) always has a lower priority than
108 any existing coroutine. 328 any existing coroutine.
109 329
110 Changing the priority of the current process will take effect 330 Changing the priority of the current coroutine will take effect
111 immediately, but changing the priority of processes in the ready 331 immediately, but changing the priority of coroutines in the ready
112 queue (but not running) will only take effect after the next 332 queue (but not running) will only take effect after the next
113 schedule (of that process). This is a bug that will be fixed in some 333 schedule (of that coroutine). This is a bug that will be fixed in
114 future version. 334 some future version.
115 335
116 $newprio = $process->nice($change) 336 $newprio = $coroutine->nice ($change)
117 Similar to "prio", but subtract the given value from the priority 337 Similar to "prio", but subtract the given value from the priority
118 (i.e. higher values mean lower priority, just as in unix). 338 (i.e. higher values mean lower priority, just as in unix).
119 339
120 $olddesc = $process->desc($newdesc) 340 $olddesc = $coroutine->desc ($newdesc)
121 Sets (or gets in case the argument is missing) the description for 341 Sets (or gets in case the argument is missing) the description for
122 this process. This is just a free-form string you can associate with 342 this coroutine. This is just a free-form string you can associate
123 a process. 343 with a coroutine.
344
345 This method simply sets the "$coroutine->{desc}" member to the given
346 string. You can modify this member directly if you wish.
347
348GLOBAL FUNCTIONS
349 Coro::nready
350 Returns the number of coroutines that are currently in the ready
351 state, i.e. that can be switched to by calling "schedule" directory
352 or indirectly. The value 0 means that the only runnable coroutine is
353 the currently running one, so "cede" would have no effect, and
354 "schedule" would cause a deadlock unless there is an idle handler
355 that wakes up some coroutines.
356
357 my $guard = Coro::guard { ... }
358 This creates and returns a guard object. Nothing happens until the
359 object gets destroyed, in which case the codeblock given as argument
360 will be executed. This is useful to free locks or other resources in
361 case of a runtime error or when the coroutine gets canceled, as in
362 both cases the guard block will be executed. The guard object
363 supports only one method, "->cancel", which will keep the codeblock
364 from being executed.
365
366 Example: set some flag and clear it again when the coroutine gets
367 canceled or the function returns:
368
369 sub do_something {
370 my $guard = Coro::guard { $busy = 0 };
371 $busy = 1;
372
373 # do something that requires $busy to be true
374 }
375
376 unblock_sub { ... }
377 This utility function takes a BLOCK or code reference and "unblocks"
378 it, returning a new coderef. Unblocking means that calling the new
379 coderef will return immediately without blocking, returning nothing,
380 while the original code ref will be called (with parameters) from
381 within another coroutine.
382
383 The reason this function exists is that many event libraries (such
384 as the venerable Event module) are not coroutine-safe (a weaker form
385 of reentrancy). This means you must not block within event
386 callbacks, otherwise you might suffer from crashes or worse. The
387 only event library currently known that is safe to use without
388 "unblock_sub" is EV.
389
390 This function allows your callbacks to block by executing them in
391 another coroutine where it is safe to block. One example where
392 blocking is handy is when you use the Coro::AIO functions to save
393 results to disk, for example.
394
395 In short: simply use "unblock_sub { ... }" instead of "sub { ... }"
396 when creating event callbacks that want to block.
397
398 If your handler does not plan to block (e.g. simply sends a message
399 to another coroutine, or puts some other coroutine into the ready
400 queue), there is no reason to use "unblock_sub".
401
402 Note that you also need to use "unblock_sub" for any other callbacks
403 that are indirectly executed by any C-based event loop. For example,
404 when you use a module that uses AnyEvent (and you use
405 Coro::AnyEvent) and it provides callbacks that are the result of
406 some event callback, then you must not block either, or use
407 "unblock_sub".
408
409 $cb = Coro::rouse_cb
410 Create and return a "rouse callback". That's a code reference that,
411 when called, will remember a copy of its arguments and notify the
412 owner coroutine of the callback.
413
414 See the next function.
415
416 @args = Coro::rouse_wait [$cb]
417 Wait for the specified rouse callback (or the last one that was
418 created in this coroutine).
419
420 As soon as the callback is invoked (or when the callback was invoked
421 before "rouse_wait"), it will return the arguments originally passed
422 to the rouse callback.
423
424 See the section HOW TO WAIT FOR A CALLBACK for an actual usage
425 example.
426
427HOW TO WAIT FOR A CALLBACK
428 It is very common for a coroutine to wait for some callback to be
429 called. This occurs naturally when you use coroutines in an otherwise
430 event-based program, or when you use event-based libraries.
431
432 These typically register a callback for some event, and call that
433 callback when the event occured. In a coroutine, however, you typically
434 want to just wait for the event, simplyifying things.
435
436 For example "AnyEvent->child" registers a callback to be called when a
437 specific child has exited:
438
439 my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... });
440
441 But from withina coroutine, you often just want to write this:
442
443 my $status = wait_for_child $pid;
444
445 Coro offers two functions specifically designed to make this easy,
446 "Coro::rouse_cb" and "Coro::rouse_wait".
447
448 The first function, "rouse_cb", generates and returns a callback that,
449 when invoked, will save it's arguments and notify the coroutine that
450 created the callback.
451
452 The second function, "rouse_wait", waits for the callback to be called
453 (by calling "schedule" to go to sleep) and returns the arguments
454 originally passed to the callback.
455
456 Using these functions, it becomes easy to write the "wait_for_child"
457 function mentioned above:
458
459 sub wait_for_child($) {
460 my ($pid) = @_;
461
462 my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb);
463
464 my ($rpid, $rstatus) = Coro::rouse_wait;
465 $rstatus
466 }
467
468 In the case where "rouse_cb" and "rouse_wait" are not flexible enough,
469 you can roll your own, using "schedule":
470
471 sub wait_for_child($) {
472 my ($pid) = @_;
473
474 # store the current coroutine in $current,
475 # and provide result variables for the closure passed to ->child
476 my $current = $Coro::current;
477 my ($done, $rstatus);
478
479 # pass a closure to ->child
480 my $watcher = AnyEvent->child (pid => $pid, cb => sub {
481 $rstatus = $_[1]; # remember rstatus
482 $done = 1; # mark $rstatus as valud
483 });
484
485 # wait until the closure has been called
486 schedule while !$done;
487
488 $rstatus
489 }
124 490
125BUGS/LIMITATIONS 491BUGS/LIMITATIONS
126 - you must make very sure that no coro is still active on global 492 fork with pthread backend
127 destruction. very bad things might happen otherwise (usually segfaults). 493 When Coro is compiled using the pthread backend (which isn't
494 recommended but required on many BSDs as their libcs are completely
495 broken), then coroutines will not survive a fork. There is no known
496 workaround except to fix your libc and use a saner backend.
128 497
498 perl process emulation ("threads")
129 - this module is not thread-safe. You should only ever use this module 499 This module is not perl-pseudo-thread-safe. You should only ever use
130 from the same thread (this requirement might be losened in the future 500 this module from the first thread (this requirement might be removed
131 to allow per-thread schedulers, but Coro::State does not yet allow 501 in the future to allow per-thread schedulers, but Coro::State does
132 this). 502 not yet allow this). I recommend disabling thread support and using
503 processes, as having the windows process emulation enabled under
504 unix roughly halves perl performance, even when not used.
505
506 coroutine switching not signal safe
507 You must not switch to another coroutine from within a signal
508 handler (only relevant with %SIG - most event libraries provide safe
509 signals).
510
511 That means you *MUST NOT* call any function that might "block" the
512 current coroutine - "cede", "schedule" "Coro::Semaphore->down" or
513 anything that calls those. Everything else, including calling
514 "ready", works.
133 515
134SEE ALSO 516SEE ALSO
517 Event-Loop integration: Coro::AnyEvent, Coro::EV, Coro::Event.
518
519 Debugging: Coro::Debug.
520
135 Support/Utility: Coro::Cont, Coro::Specific, Coro::State, Coro::Util. 521 Support/Utility: Coro::Specific, Coro::Util.
136 522
137 Locking/IPC: Coro::Signal, Coro::Channel, Coro::Semaphore, 523 Locking and IPC: Coro::Signal, Coro::Channel, Coro::Semaphore,
138 Coro::SemaphoreSet, Coro::RWLock. 524 Coro::SemaphoreSet, Coro::RWLock.
139 525
140 Event/IO: Coro::Timer, Coro::Event, Coro::Handle, Coro::Socket, 526 I/O and Timers: Coro::Timer, Coro::Handle, Coro::Socket, Coro::AIO.
527
528 Compatibility with other modules: Coro::LWP (but see also AnyEvent::HTTP
529 for a better-working alternative), Coro::BDB, Coro::Storable,
141 Coro::Select. 530 Coro::Select.
142 531
143 Embedding: <Coro:MakeMaker> 532 XS API: Coro::MakeMaker.
533
534 Low level Configuration, Thread Environment, Continuations: Coro::State.
144 535
145AUTHOR 536AUTHOR
146 Marc Lehmann <schmorp@schmorp.de> 537 Marc Lehmann <schmorp@schmorp.de>
147 http://home.schmorp.de/ 538 http://home.schmorp.de/
148 539

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines