/
usr
/
share
/
doc
/
python3-docs
/
html
/
library
/
/usr/share/doc/python3-docs/html/library
mkdir
upload
Name
Size
Mode
Actions
2to3.html
61709
0644
edit
dl
rm
abc.html
41394
0644
edit
dl
rm
aifc.html
28114
0644
edit
dl
rm
allos.html
32236
0644
edit
dl
rm
archiving.html
11992
0644
edit
dl
rm
argparse.html
274984
0644
edit
dl
rm
array.html
33547
0644
edit
dl
rm
ast.html
39595
0644
edit
dl
rm
asynchat.html
32546
0644
edit
dl
rm
asyncio-dev.html
51869
0644
edit
dl
rm
asyncio-eventloop.html
111215
0644
edit
dl
rm
asyncio-eventloops.html
33026
0644
edit
dl
rm
asyncio-protocol.html
87431
0644
edit
dl
rm
asyncio-queue.html
23957
0644
edit
dl
rm
asyncio-stream.html
61005
0644
edit
dl
rm
asyncio-subprocess.html
58015
0644
edit
dl
rm
asyncio-sync.html
35678
0644
edit
dl
rm
asyncio-task.html
83968
0644
edit
dl
rm
asyncio.html
28026
0644
edit
dl
rm
asyncore.html
42706
0644
edit
dl
rm
atexit.html
18433
0644
edit
dl
rm
audioop.html
35442
0644
edit
dl
rm
base64.html
36454
0644
edit
dl
rm
bdb.html
43423
0644
edit
dl
rm
binary.html
12723
0644
edit
dl
rm
binascii.html
24745
0644
edit
dl
rm
binhex.html
11669
0644
edit
dl
rm
bisect.html
25602
0644
edit
dl
rm
builtins.html
11604
0644
edit
dl
rm
bz2.html
33358
0644
edit
dl
rm
calendar.html
39539
0644
edit
dl
rm
cgi.html
55881
0644
edit
dl
rm
cgitb.html
12765
0644
edit
dl
rm
chunk.html
16872
0644
edit
dl
rm
cmath.html
34171
0644
edit
dl
rm
cmd.html
43811
0644
edit
dl
rm
code.html
27886
0644
edit
dl
rm
codecs.html
134071
0644
edit
dl
rm
codeop.html
14304
0644
edit
dl
rm
collections.abc.html
60912
0644
edit
dl
rm
collections.html
154946
0644
edit
dl
rm
colorsys.html
12627
0644
edit
dl
rm
compileall.html
28263
0644
edit
dl
rm
concurrency.html
21203
0644
edit
dl
rm
concurrent.futures.html
60660
0644
edit
dl
rm
concurrent.html
7959
0644
edit
dl
rm
configparser.html
141052
0644
edit
dl
rm
constants.html
17500
0644
edit
dl
rm
contextlib.html
88801
0644
edit
dl
rm
copy.html
13841
0644
edit
dl
rm
copyreg.html
14725
0644
edit
dl
rm
crypt.html
20331
0644
edit
dl
rm
crypto.html
10914
0644
edit
dl
rm
csv.html
69043
0644
edit
dl
rm
ctypes.html
264529
0644
edit
dl
rm
curses.ascii.html
25197
0644
edit
dl
rm
curses.html
175551
0644
edit
dl
rm
curses.panel.html
16706
0644
edit
dl
rm
custominterp.html
8734
0644
edit
dl
rm
datatypes.html
23950
0644
edit
dl
rm
datetime.html
306435
0644
edit
dl
rm
dbm.html
43119
0644
edit
dl
rm
debug.html
13983
0644
edit
dl
rm
decimal.html
233486
0644
edit
dl
rm
development.html
25123
0644
edit
dl
rm
difflib.html
96156
0644
edit
dl
rm
dis.html
106191
0644
edit
dl
rm
distribution.html
10506
0644
edit
dl
rm
distutils.html
10884
0644
edit
dl
rm
doctest.html
179752
0644
edit
dl
rm
dummy_threading.html
9316
0644
edit
dl
rm
email.charset.html
26431
0644
edit
dl
rm
email.compat32-message.html
86150
0644
edit
dl
rm
email.contentmanager.html
30028
0644
edit
dl
rm
email.encoders.html
14250
0644
edit
dl
rm
email.errors.html
19704
0644
edit
dl
rm
email.examples.html
57872
0644
edit
dl
rm
email.generator.html
41798
0644
edit
dl
rm
email.header.html
31219
0644
edit
dl
rm
email.headerregistry.html
57670
0644
edit
dl
rm
email.html
27741
0644
edit
dl
rm
email.iterators.html
13532
0644
edit
dl
rm
email.message.html
87210
0644
edit
dl
rm
email.mime.html
36081
0644
edit
dl
rm
email.parser.html
47430
0644
edit
dl
rm
email.policy.html
75241
0644
edit
dl
rm
email.util.html
33853
0644
edit
dl
rm
ensurepip.html
18700
0644
edit
dl
rm
enum.html
133949
0644
edit
dl
rm
errno.html
41331
0644
edit
dl
rm
exceptions.html
85151
0644
edit
dl
rm
faulthandler.html
23396
0644
edit
dl
rm
fcntl.html
27321
0644
edit
dl
rm
filecmp.html
25036
0644
edit
dl
rm
fileformats.html
11129
0644
edit
dl
rm
fileinput.html
30030
0644
edit
dl
rm
filesys.html
13418
0644
edit
dl
rm
fnmatch.html
16987
0644
edit
dl
rm
formatter.html
37666
0644
edit
dl
rm
fpectl.html
17538
0644
edit
dl
rm
fractions.html
29918
0644
edit
dl
rm
frameworks.html
13471
0644
edit
dl
rm
ftplib.html
54429
0644
edit
dl
rm
functional.html
9002
0644
edit
dl
rm
functions.html
201486
0644
edit
dl
rm
functools.html
64951
0644
edit
dl
rm
gc.html
29524
0644
edit
dl
rm
getopt.html
25353
0644
edit
dl
rm
getpass.html
12061
0644
edit
dl
rm
gettext.html
76641
0644
edit
dl
rm
glob.html
18432
0644
edit
dl
rm
grp.html
12383
0644
edit
dl
rm
gzip.html
32669
0644
edit
dl
rm
hashlib.html
79554
0644
edit
dl
rm
heapq.html
35529
0644
edit
dl
rm
hmac.html
17827
0644
edit
dl
rm
html.entities.html
11361
0644
edit
dl
rm
html.html
11108
0644
edit
dl
rm
html.parser.html
41842
0644
edit
dl
rm
http.client.html
65250
0644
edit
dl
rm
http.cookiejar.html
96195
0644
edit
dl
rm
http.cookies.html
39329
0644
edit
dl
rm
http.html
37602
0644
edit
dl
rm
http.server.html
58191
0644
edit
dl
rm
i18n.html
10464
0644
edit
dl
rm
idle.html
48412
0644
edit
dl
rm
imaplib.html
67339
0644
edit
dl
rm
imghdr.html
13456
0644
edit
dl
rm
imp.html
48153
0644
edit
dl
rm
importlib.html
173109
0644
edit
dl
rm
index.html
67768
0644
edit
dl
rm
inspect.html
130355
0644
edit
dl
rm
internet.html
31087
0644
edit
dl
rm
intro.html
9904
0644
edit
dl
rm
io.html
122685
0644
edit
dl
rm
ipaddress.html
105873
0644
edit
dl
rm
ipc.html
33743
0644
edit
dl
rm
itertools.html
132824
0644
edit
dl
rm
json.html
81078
0644
edit
dl
rm
keyword.html
8918
0644
edit
dl
rm
language.html
13648
0644
edit
dl
rm
linecache.html
13492
0644
edit
dl
rm
locale.html
61540
0644
edit
dl
rm
logging.config.html
85489
0644
edit
dl
rm
logging.handlers.html
112397
0644
edit
dl
rm
logging.html
134850
0644
edit
dl
rm
lzma.html
56484
0644
edit
dl
rm
macpath.html
9257
0644
edit
dl
rm
mailbox.html
157315
0644
edit
dl
rm
mailcap.html
14676
0644
edit
dl
rm
markup.html
19356
0644
edit
dl
rm
marshal.html
18317
0644
edit
dl
rm
math.html
53661
0644
edit
dl
rm
mimetypes.html
31410
0644
edit
dl
rm
misc.html
8123
0644
edit
dl
rm
mm.html
10022
0644
edit
dl
rm
mmap.html
34294
0644
edit
dl
rm
modulefinder.html
18559
0644
edit
dl
rm
modules.html
10914
0644
edit
dl
rm
msilib.html
57205
0644
edit
dl
rm
msvcrt.html
21989
0644
edit
dl
rm
multiprocessing.html
365487
0644
edit
dl
rm
netdata.html
17470
0644
edit
dl
rm
netrc.html
14568
0644
edit
dl
rm
nis.html
11659
0644
edit
dl
rm
nntplib.html
69601
0644
edit
dl
rm
numbers.html
41432
0644
edit
dl
rm
numeric.html
15535
0644
edit
dl
rm
operator.html
81460
0644
edit
dl
rm
optparse.html
249942
0644
edit
dl
rm
os.html
398039
0644
edit
dl
rm
os.path.html
53818
0644
edit
dl
rm
ossaudiodev.html
47947
0644
edit
dl
rm
othergui.html
10256
0644
edit
dl
rm
parser.html
42408
0644
edit
dl
rm
pathlib.html
116726
0644
edit
dl
rm
pdb.html
52661
0644
edit
dl
rm
persistence.html
15281
0644
edit
dl
rm
pickle.html
115052
0644
edit
dl
rm
pickletools.html
17094
0644
edit
dl
rm
pipes.html
15991
0644
edit
dl
rm
pkgutil.html
31878
0644
edit
dl
rm
platform.html
33728
0644
edit
dl
rm
plistlib.html
29290
0644
edit
dl
rm
poplib.html
30940
0644
edit
dl
rm
posix.html
17608
0644
edit
dl
rm
pprint.html
41969
0644
edit
dl
rm
profile.html
71848
0644
edit
dl
rm
pty.html
17594
0644
edit
dl
rm
pwd.html
13098
0644
edit
dl
rm
pyclbr.html
16520
0644
edit
dl
rm
pydoc.html
15991
0644
edit
dl
rm
pyexpat.html
88938
0644
edit
dl
rm
python.html
17133
0644
edit
dl
rm
py_compile.html
15508
0644
edit
dl
rm
queue.html
28199
0644
edit
dl
rm
quopri.html
13858
0644
edit
dl
rm
random.html
60646
0644
edit
dl
rm
re.html
191176
0644
edit
dl
rm
readline.html
42133
0644
edit
dl
rm
reprlib.html
24964
0644
edit
dl
rm
resource.html
36552
0644
edit
dl
rm
rlcompleter.html
14392
0644
edit
dl
rm
runpy.html
26607
0644
edit
dl
rm
sched.html
20034
0644
edit
dl
rm
secrets.html
24734
0644
edit
dl
rm
select.html
62819
0644
edit
dl
rm
selectors.html
35845
0644
edit
dl
rm
shelve.html
28777
0644
edit
dl
rm
shlex.html
48979
0644
edit
dl
rm
shutil.html
74207
0644
edit
dl
rm
signal.html
55064
0644
edit
dl
rm
site.html
32242
0644
edit
dl
rm
smtpd.html
35892
0644
edit
dl
rm
smtplib.html
68433
0644
edit
dl
rm
sndhdr.html
12439
0644
edit
dl
rm
socket.html
196077
0644
edit
dl
rm
socketserver.html
81918
0644
edit
dl
rm
spwd.html
12328
0644
edit
dl
rm
sqlite3.html
161872
0644
edit
dl
rm
ssl.html
266327
0644
edit
dl
rm
stat.html
44722
0644
edit
dl
rm
statistics.html
50050
0644
edit
dl
rm
stdtypes.html
465658
0644
edit
dl
rm
string.html
95262
0644
edit
dl
rm
stringprep.html
18654
0644
edit
dl
rm
struct.html
51100
0644
edit
dl
rm
subprocess.html
141926
0644
edit
dl
rm
sunau.html
31757
0644
edit
dl
rm
superseded.html
13781
0644
edit
dl
rm
symbol.html
8848
0644
edit
dl
rm
symtable.html
26112
0644
edit
dl
rm
sys.html
141670
0644
edit
dl
rm
sysconfig.html
30259
0644
edit
dl
rm
syslog.html
21026
0644
edit
dl
rm
tabnanny.html
12269
0644
edit
dl
rm
tarfile.html
96758
0644
edit
dl
rm
telnetlib.html
30409
0644
edit
dl
rm
tempfile.html
41394
0644
edit
dl
rm
termios.html
18181
0644
edit
dl
rm
test.html
78555
0644
edit
dl
rm
text.html
13786
0644
edit
dl
rm
textwrap.html
37998
0644
edit
dl
rm
threading.html
103464
0644
edit
dl
rm
time.html
79629
0644
edit
dl
rm
timeit.html
45249
0644
edit
dl
rm
tk.html
23299
0644
edit
dl
rm
tkinter.html
82932
0644
edit
dl
rm
tkinter.scrolledtext.html
9957
0644
edit
dl
rm
tkinter.tix.html
51858
0644
edit
dl
rm
tkinter.ttk.html
110673
0644
edit
dl
rm
token.html
22660
0644
edit
dl
rm
tokenize.html
32149
0644
edit
dl
rm
trace.html
29145
0644
edit
dl
rm
traceback.html
57588
0644
edit
dl
rm
tracemalloc.html
101144
0644
edit
dl
rm
tty.html
10540
0644
edit
dl
rm
turtle.html
250367
0644
edit
dl
rm
types.html
37060
0644
edit
dl
rm
typing.html
139175
0644
edit
dl
rm
undoc.html
9181
0644
edit
dl
rm
unicodedata.html
21108
0644
edit
dl
rm
unittest.html
250689
0644
edit
dl
rm
unittest.mock-examples.html
168144
0644
edit
dl
rm
unittest.mock.html
300089
0644
edit
dl
rm
unix.html
11780
0644
edit
dl
rm
urllib.error.html
14474
0644
edit
dl
rm
urllib.html
9566
0644
edit
dl
rm
urllib.parse.html
76334
0644
edit
dl
rm
urllib.request.html
177199
0644
edit
dl
rm
urllib.robotparser.html
17156
0644
edit
dl
rm
uu.html
12209
0644
edit
dl
rm
uuid.html
31957
0644
edit
dl
rm
venv.html
73909
0644
edit
dl
rm
warnings.html
50320
0644
edit
dl
rm
wave.html
29868
0644
edit
dl
rm
weakref.html
65292
0644
edit
dl
rm
webbrowser.html
26901
0644
edit
dl
rm
windows.html
10626
0644
edit
dl
rm
winreg.html
66730
0644
edit
dl
rm
winsound.html
21268
0644
edit
dl
rm
wsgiref.html
94492
0644
edit
dl
rm
xdrlib.html
33751
0644
edit
dl
rm
xml.dom.html
97570
0644
edit
dl
rm
xml.dom.minidom.html
41481
0644
edit
dl
rm
xml.dom.pulldom.html
24214
0644
edit
dl
rm
xml.etree.elementtree.html
135491
0644
edit
dl
rm
xml.html
19261
0644
edit
dl
rm
xml.sax.handler.html
42659
0644
edit
dl
rm
xml.sax.html
25515
0644
edit
dl
rm
xml.sax.reader.html
45869
0644
edit
dl
rm
xml.sax.utils.html
16928
0644
edit
dl
rm
xmlrpc.client.html
71947
0644
edit
dl
rm
xmlrpc.html
8535
0644
edit
dl
rm
xmlrpc.server.html
49195
0644
edit
dl
rm
zipapp.html
45105
0644
edit
dl
rm
zipfile.html
80039
0644
edit
dl
rm
zipimport.html
23052
0644
edit
dl
rm
zlib.html
34557
0644
edit
dl
rm
_dummy_thread.html
9193
0644
edit
dl
rm
_thread.html
22588
0644
edit
dl
rm
__future__.html
15792
0644
edit
dl
rm
__main__.html
9019
0644
edit
dl
rm
Edit:
/usr/share/doc/python3-docs/html/library/selectors.html
(35845B)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>18.4. selectors — High-level I/O multiplexing — Python 3.6.7 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.6.7 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="18.5. asyncio — Asynchronous I/O, event loop, coroutines and tasks" href="asyncio.html" /> <link rel="prev" title="18.3. select — Waiting for I/O completion" href="select.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/selectors.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="asyncio.html" title="18.5. asyncio — Asynchronous I/O, event loop, coroutines and tasks" accesskey="N">next</a> |</li> <li class="right" > <a href="select.html" title="18.3. select — Waiting for I/O completion" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="ipc.html" accesskey="U">18. Interprocess Communication and Networking</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-selectors"> <span id="selectors-high-level-i-o-multiplexing"></span><h1>18.4. <a class="reference internal" href="#module-selectors" title="selectors: High-level I/O multiplexing."><code class="xref py py-mod docutils literal notranslate"><span class="pre">selectors</span></code></a> — High-level I/O multiplexing<a class="headerlink" href="#module-selectors" title="Permalink to this headline">¶</a></h1> <div class="versionadded"> <p><span class="versionmodified">New in version 3.4.</span></p> </div> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.6/Lib/selectors.py">Lib/selectors.py</a></p> <hr class="docutils" /> <div class="section" id="introduction"> <h2>18.4.1. Introduction<a class="headerlink" href="#introduction" title="Permalink to this headline">¶</a></h2> <p>This module allows high-level and efficient I/O multiplexing, built upon the <a class="reference internal" href="select.html#module-select" title="select: Wait for I/O completion on multiple streams."><code class="xref py py-mod docutils literal notranslate"><span class="pre">select</span></code></a> module primitives. Users are encouraged to use this module instead, unless they want precise control over the OS-level primitives used.</p> <p>It defines a <a class="reference internal" href="#selectors.BaseSelector" title="selectors.BaseSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">BaseSelector</span></code></a> abstract base class, along with several concrete implementations (<a class="reference internal" href="#selectors.KqueueSelector" title="selectors.KqueueSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">KqueueSelector</span></code></a>, <a class="reference internal" href="#selectors.EpollSelector" title="selectors.EpollSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">EpollSelector</span></code></a>…), that can be used to wait for I/O readiness notification on multiple file objects. In the following, “file object” refers to any object with a <code class="xref py py-meth docutils literal notranslate"><span class="pre">fileno()</span></code> method, or a raw file descriptor. See <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>.</p> <p><a class="reference internal" href="#selectors.DefaultSelector" title="selectors.DefaultSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">DefaultSelector</span></code></a> is an alias to the most efficient implementation available on the current platform: this should be the default choice for most users.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The type of file objects supported depends on the platform: on Windows, sockets are supported, but not pipes, whereas on Unix, both are supported (some other types may be supported as well, such as fifos or special file devices).</p> </div> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt><a class="reference internal" href="select.html#module-select" title="select: Wait for I/O completion on multiple streams."><code class="xref py py-mod docutils literal notranslate"><span class="pre">select</span></code></a></dt> <dd>Low-level I/O multiplexing module.</dd> </dl> </div> </div> <div class="section" id="classes"> <h2>18.4.2. Classes<a class="headerlink" href="#classes" title="Permalink to this headline">¶</a></h2> <p>Classes hierarchy:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">BaseSelector</span> <span class="o">+--</span> <span class="n">SelectSelector</span> <span class="o">+--</span> <span class="n">PollSelector</span> <span class="o">+--</span> <span class="n">EpollSelector</span> <span class="o">+--</span> <span class="n">DevpollSelector</span> <span class="o">+--</span> <span class="n">KqueueSelector</span> </pre></div> </div> <p>In the following, <em>events</em> is a bitwise mask indicating which I/O events should be waited for on a given file object. It can be a combination of the modules constants below:</p> <blockquote> <div><table border="1" class="docutils"> <colgroup> <col width="33%" /> <col width="67%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Constant</th> <th class="head">Meaning</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="xref py py-const docutils literal notranslate"><span class="pre">EVENT_READ</span></code></td> <td>Available for read</td> </tr> <tr class="row-odd"><td><code class="xref py py-const docutils literal notranslate"><span class="pre">EVENT_WRITE</span></code></td> <td>Available for write</td> </tr> </tbody> </table> </div></blockquote> <dl class="class"> <dt id="selectors.SelectorKey"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">SelectorKey</code><a class="headerlink" href="#selectors.SelectorKey" title="Permalink to this definition">¶</a></dt> <dd><p>A <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> is a <a class="reference internal" href="collections.html#collections.namedtuple" title="collections.namedtuple"><code class="xref py py-class docutils literal notranslate"><span class="pre">namedtuple</span></code></a> used to associate a file object to its underlying file descriptor, selected event mask and attached data. It is returned by several <a class="reference internal" href="#selectors.BaseSelector" title="selectors.BaseSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">BaseSelector</span></code></a> methods.</p> <dl class="attribute"> <dt id="selectors.SelectorKey.fileobj"> <code class="descname">fileobj</code><a class="headerlink" href="#selectors.SelectorKey.fileobj" title="Permalink to this definition">¶</a></dt> <dd><p>File object registered.</p> </dd></dl> <dl class="attribute"> <dt id="selectors.SelectorKey.fd"> <code class="descname">fd</code><a class="headerlink" href="#selectors.SelectorKey.fd" title="Permalink to this definition">¶</a></dt> <dd><p>Underlying file descriptor.</p> </dd></dl> <dl class="attribute"> <dt id="selectors.SelectorKey.events"> <code class="descname">events</code><a class="headerlink" href="#selectors.SelectorKey.events" title="Permalink to this definition">¶</a></dt> <dd><p>Events that must be waited for on this file object.</p> </dd></dl> <dl class="attribute"> <dt id="selectors.SelectorKey.data"> <code class="descname">data</code><a class="headerlink" href="#selectors.SelectorKey.data" title="Permalink to this definition">¶</a></dt> <dd><p>Optional opaque data associated to this file object: for example, this could be used to store a per-client session ID.</p> </dd></dl> </dd></dl> <dl class="class"> <dt id="selectors.BaseSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">BaseSelector</code><a class="headerlink" href="#selectors.BaseSelector" title="Permalink to this definition">¶</a></dt> <dd><p>A <a class="reference internal" href="#selectors.BaseSelector" title="selectors.BaseSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">BaseSelector</span></code></a> is used to wait for I/O event readiness on multiple file objects. It supports file stream registration, unregistration, and a method to wait for I/O events on those streams, with an optional timeout. It’s an abstract base class, so cannot be instantiated. Use <a class="reference internal" href="#selectors.DefaultSelector" title="selectors.DefaultSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">DefaultSelector</span></code></a> instead, or one of <a class="reference internal" href="#selectors.SelectSelector" title="selectors.SelectSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectSelector</span></code></a>, <a class="reference internal" href="#selectors.KqueueSelector" title="selectors.KqueueSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">KqueueSelector</span></code></a> etc. if you want to specifically use an implementation, and your platform supports it. <a class="reference internal" href="#selectors.BaseSelector" title="selectors.BaseSelector"><code class="xref py py-class docutils literal notranslate"><span class="pre">BaseSelector</span></code></a> and its concrete implementations support the <a class="reference internal" href="../glossary.html#term-context-manager"><span class="xref std std-term">context manager</span></a> protocol.</p> <dl class="method"> <dt id="selectors.BaseSelector.register"> <em class="property">abstractmethod </em><code class="descname">register</code><span class="sig-paren">(</span><em>fileobj</em>, <em>events</em>, <em>data=None</em><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.register" title="Permalink to this definition">¶</a></dt> <dd><p>Register a file object for selection, monitoring it for I/O events.</p> <p><em>fileobj</em> is the file object to monitor. It may either be an integer file descriptor or an object with a <code class="docutils literal notranslate"><span class="pre">fileno()</span></code> method. <em>events</em> is a bitwise mask of events to monitor. <em>data</em> is an opaque object.</p> <p>This returns a new <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance, or raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> in case of invalid event mask or file descriptor, or <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> if the file object is already registered.</p> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.unregister"> <em class="property">abstractmethod </em><code class="descname">unregister</code><span class="sig-paren">(</span><em>fileobj</em><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.unregister" title="Permalink to this definition">¶</a></dt> <dd><p>Unregister a file object from selection, removing it from monitoring. A file object shall be unregistered prior to being closed.</p> <p><em>fileobj</em> must be a file object previously registered.</p> <p>This returns the associated <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance, or raises a <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> if <em>fileobj</em> is not registered. It will raise <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if <em>fileobj</em> is invalid (e.g. it has no <code class="docutils literal notranslate"><span class="pre">fileno()</span></code> method or its <code class="docutils literal notranslate"><span class="pre">fileno()</span></code> method has an invalid return value).</p> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.modify"> <code class="descname">modify</code><span class="sig-paren">(</span><em>fileobj</em>, <em>events</em>, <em>data=None</em><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.modify" title="Permalink to this definition">¶</a></dt> <dd><p>Change a registered file object’s monitored events or attached data.</p> <p>This is equivalent to <code class="xref py py-meth docutils literal notranslate"><span class="pre">BaseSelector.unregister(fileobj)()</span></code> followed by <code class="xref py py-meth docutils literal notranslate"><span class="pre">BaseSelector.register(fileobj,</span> <span class="pre">events,</span> <span class="pre">data)()</span></code>, except that it can be implemented more efficiently.</p> <p>This returns a new <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance, or raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> in case of invalid event mask or file descriptor, or <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> if the file object is not registered.</p> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.select"> <em class="property">abstractmethod </em><code class="descname">select</code><span class="sig-paren">(</span><em>timeout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.select" title="Permalink to this definition">¶</a></dt> <dd><p>Wait until some registered file objects become ready, or the timeout expires.</p> <p>If <code class="docutils literal notranslate"><span class="pre">timeout</span> <span class="pre">></span> <span class="pre">0</span></code>, this specifies the maximum wait time, in seconds. If <code class="docutils literal notranslate"><span class="pre">timeout</span> <span class="pre"><=</span> <span class="pre">0</span></code>, the call won’t block, and will report the currently ready file objects. If <em>timeout</em> is <code class="docutils literal notranslate"><span class="pre">None</span></code>, the call will block until a monitored file object becomes ready.</p> <p>This returns a list of <code class="docutils literal notranslate"><span class="pre">(key,</span> <span class="pre">events)</span></code> tuples, one for each ready file object.</p> <p><em>key</em> is the <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance corresponding to a ready file object. <em>events</em> is a bitmask of events ready on this file object.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">This method can return before any file object becomes ready or the timeout has elapsed if the current process receives a signal: in this case, an empty list will be returned.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.5: </span>The selector is now retried with a recomputed timeout when interrupted by a signal if the signal handler did not raise an exception (see <span class="target" id="index-0"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0475"><strong>PEP 475</strong></a> for the rationale), instead of returning an empty list of events before the timeout.</p> </div> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.close" title="Permalink to this definition">¶</a></dt> <dd><p>Close the selector.</p> <p>This must be called to make sure that any underlying resource is freed. The selector shall not be used once it has been closed.</p> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.get_key"> <code class="descname">get_key</code><span class="sig-paren">(</span><em>fileobj</em><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.get_key" title="Permalink to this definition">¶</a></dt> <dd><p>Return the key associated with a registered file object.</p> <p>This returns the <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance associated to this file object, or raises <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> if the file object is not registered.</p> </dd></dl> <dl class="method"> <dt id="selectors.BaseSelector.get_map"> <em class="property">abstractmethod </em><code class="descname">get_map</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#selectors.BaseSelector.get_map" title="Permalink to this definition">¶</a></dt> <dd><p>Return a mapping of file objects to selector keys.</p> <p>This returns a <a class="reference internal" href="collections.abc.html#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">Mapping</span></code></a> instance mapping registered file objects to their associated <a class="reference internal" href="#selectors.SelectorKey" title="selectors.SelectorKey"><code class="xref py py-class docutils literal notranslate"><span class="pre">SelectorKey</span></code></a> instance.</p> </dd></dl> </dd></dl> <dl class="class"> <dt id="selectors.DefaultSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">DefaultSelector</code><a class="headerlink" href="#selectors.DefaultSelector" title="Permalink to this definition">¶</a></dt> <dd><p>The default selector class, using the most efficient implementation available on the current platform. This should be the default choice for most users.</p> </dd></dl> <dl class="class"> <dt id="selectors.SelectSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">SelectSelector</code><a class="headerlink" href="#selectors.SelectSelector" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="select.html#select.select" title="select.select"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.select()</span></code></a>-based selector.</p> </dd></dl> <dl class="class"> <dt id="selectors.PollSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">PollSelector</code><a class="headerlink" href="#selectors.PollSelector" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="select.html#select.poll" title="select.poll"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.poll()</span></code></a>-based selector.</p> </dd></dl> <dl class="class"> <dt id="selectors.EpollSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">EpollSelector</code><a class="headerlink" href="#selectors.EpollSelector" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="select.html#select.epoll" title="select.epoll"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.epoll()</span></code></a>-based selector.</p> <dl class="method"> <dt id="selectors.EpollSelector.fileno"> <code class="descname">fileno</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#selectors.EpollSelector.fileno" title="Permalink to this definition">¶</a></dt> <dd><p>This returns the file descriptor used by the underlying <a class="reference internal" href="select.html#select.epoll" title="select.epoll"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.epoll()</span></code></a> object.</p> </dd></dl> </dd></dl> <dl class="class"> <dt id="selectors.DevpollSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">DevpollSelector</code><a class="headerlink" href="#selectors.DevpollSelector" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="select.html#select.devpoll" title="select.devpoll"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.devpoll()</span></code></a>-based selector.</p> <dl class="method"> <dt id="selectors.DevpollSelector.fileno"> <code class="descname">fileno</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#selectors.DevpollSelector.fileno" title="Permalink to this definition">¶</a></dt> <dd><p>This returns the file descriptor used by the underlying <a class="reference internal" href="select.html#select.devpoll" title="select.devpoll"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.devpoll()</span></code></a> object.</p> </dd></dl> <div class="versionadded"> <p><span class="versionmodified">New in version 3.5.</span></p> </div> </dd></dl> <dl class="class"> <dt id="selectors.KqueueSelector"> <em class="property">class </em><code class="descclassname">selectors.</code><code class="descname">KqueueSelector</code><a class="headerlink" href="#selectors.KqueueSelector" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="select.html#select.kqueue" title="select.kqueue"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.kqueue()</span></code></a>-based selector.</p> <dl class="method"> <dt id="selectors.KqueueSelector.fileno"> <code class="descname">fileno</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#selectors.KqueueSelector.fileno" title="Permalink to this definition">¶</a></dt> <dd><p>This returns the file descriptor used by the underlying <a class="reference internal" href="select.html#select.kqueue" title="select.kqueue"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.kqueue()</span></code></a> object.</p> </dd></dl> </dd></dl> </div> <div class="section" id="examples"> <h2>18.4.3. Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2> <p>Here is a simple echo server implementation:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">selectors</span> <span class="kn">import</span> <span class="nn">socket</span> <span class="n">sel</span> <span class="o">=</span> <span class="n">selectors</span><span class="o">.</span><span class="n">DefaultSelector</span><span class="p">()</span> <span class="k">def</span> <span class="nf">accept</span><span class="p">(</span><span class="n">sock</span><span class="p">,</span> <span class="n">mask</span><span class="p">):</span> <span class="n">conn</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">sock</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span> <span class="c1"># Should be ready</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'accepted'</span><span class="p">,</span> <span class="n">conn</span><span class="p">,</span> <span class="s1">'from'</span><span class="p">,</span> <span class="n">addr</span><span class="p">)</span> <span class="n">conn</span><span class="o">.</span><span class="n">setblocking</span><span class="p">(</span><span class="kc">False</span><span class="p">)</span> <span class="n">sel</span><span class="o">.</span><span class="n">register</span><span class="p">(</span><span class="n">conn</span><span class="p">,</span> <span class="n">selectors</span><span class="o">.</span><span class="n">EVENT_READ</span><span class="p">,</span> <span class="n">read</span><span class="p">)</span> <span class="k">def</span> <span class="nf">read</span><span class="p">(</span><span class="n">conn</span><span class="p">,</span> <span class="n">mask</span><span class="p">):</span> <span class="n">data</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1000</span><span class="p">)</span> <span class="c1"># Should be ready</span> <span class="k">if</span> <span class="n">data</span><span class="p">:</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'echoing'</span><span class="p">,</span> <span class="nb">repr</span><span class="p">(</span><span class="n">data</span><span class="p">),</span> <span class="s1">'to'</span><span class="p">,</span> <span class="n">conn</span><span class="p">)</span> <span class="n">conn</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">data</span><span class="p">)</span> <span class="c1"># Hope it won't block</span> <span class="k">else</span><span class="p">:</span> <span class="nb">print</span><span class="p">(</span><span class="s1">'closing'</span><span class="p">,</span> <span class="n">conn</span><span class="p">)</span> <span class="n">sel</span><span class="o">.</span><span class="n">unregister</span><span class="p">(</span><span class="n">conn</span><span class="p">)</span> <span class="n">conn</span><span class="o">.</span><span class="n">close</span><span class="p">()</span> <span class="n">sock</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">()</span> <span class="n">sock</span><span class="o">.</span><span class="n">bind</span><span class="p">((</span><span class="s1">'localhost'</span><span class="p">,</span> <span class="mi">1234</span><span class="p">))</span> <span class="n">sock</span><span class="o">.</span><span class="n">listen</span><span class="p">(</span><span class="mi">100</span><span class="p">)</span> <span class="n">sock</span><span class="o">.</span><span class="n">setblocking</span><span class="p">(</span><span class="kc">False</span><span class="p">)</span> <span class="n">sel</span><span class="o">.</span><span class="n">register</span><span class="p">(</span><span class="n">sock</span><span class="p">,</span> <span class="n">selectors</span><span class="o">.</span><span class="n">EVENT_READ</span><span class="p">,</span> <span class="n">accept</span><span class="p">)</span> <span class="k">while</span> <span class="kc">True</span><span class="p">:</span> <span class="n">events</span> <span class="o">=</span> <span class="n">sel</span><span class="o">.</span><span class="n">select</span><span class="p">()</span> <span class="k">for</span> <span class="n">key</span><span class="p">,</span> <span class="n">mask</span> <span class="ow">in</span> <span class="n">events</span><span class="p">:</span> <span class="n">callback</span> <span class="o">=</span> <span class="n">key</span><span class="o">.</span><span class="n">data</span> <span class="n">callback</span><span class="p">(</span><span class="n">key</span><span class="o">.</span><span class="n">fileobj</span><span class="p">,</span> <span class="n">mask</span><span class="p">)</span> </pre></div> </div> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">18.4. <code class="docutils literal notranslate"><span class="pre">selectors</span></code> — High-level I/O multiplexing</a><ul> <li><a class="reference internal" href="#introduction">18.4.1. Introduction</a></li> <li><a class="reference internal" href="#classes">18.4.2. Classes</a></li> <li><a class="reference internal" href="#examples">18.4.3. Examples</a></li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="select.html" title="previous chapter">18.3. <code class="docutils literal notranslate"><span class="pre">select</span></code> — Waiting for I/O completion</a></p> <h4>Next topic</h4> <p class="topless"><a href="asyncio.html" title="next chapter">18.5. <code class="docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O, event loop, coroutines and tasks</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.6/Doc/library/selectors.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="asyncio.html" title="18.5. asyncio — Asynchronous I/O, event loop, coroutines and tasks" >next</a> |</li> <li class="right" > <a href="select.html" title="18.3. select — Waiting for I/O completion" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 Documentation</a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="ipc.html" >18. Interprocess Communication and Networking</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2023, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Dec 18, 2023. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.7.6. </div> </body> </html>
Save
cmd:
run