1Handle(3) User Contributed Perl Documentation Handle(3)
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6 Coro::Handle - non-blocking I/O with a blocking interface.
7
9 use Coro::Handle;
10
12 This module is an AnyEvent user, you need to make sure that you use and
13 run a supported event loop.
14 This module implements IO-handles in a coroutine-compatible way, that
16 is, other coroutines can run while reads or writes block on the handle.
17 It does so by using AnyEvent to wait for readable/writable data,
19 allowing other coroutines to run while one coroutine waits for I/O.
20 Coro::Handle does NOT inherit from IO::Handle but uses tied objects.
22 If at all possible, you should always prefer method calls on the handle
24 object over invoking tied methods, i.e.:
25 $fh->print ($str); # NOT print $fh $str;
27 my $line = $fh->readline; # NOT my $line = <$fh>;
28 The reason is that perl recurses within the interpreter when invoking
30 tie magic, forcing the (temporary) allocation of a (big) stack. If you
31 have lots of socket connections and they happen to wait in e.g. <$fh>,
32 then they would all have a costly C coroutine associated with them.
33 $fh = new_from_fh Coro::Handle $fhandle [, arg => value...]
35 Create a new non-blocking io-handle using the given perl-
36 filehandle. Returns "undef" if no filehandle is given. The only
37 other supported argument is "timeout", which sets a timeout for
38 each operation.
39 $fh = unblock $fh
41 This is a convenience function that just calls "new_from_fh" on the
42 given filehandle. Use it to replace a normal perl filehandle by a
43 non-(coroutine-)blocking equivalent.
44 $fh->writable, $fh->readable
46 Wait until the filehandle is readable or writable (and return true)
47 or until an error condition happens (and return false).
48 $fh->readline ([$terminator])
50 Similar to the builtin of the same name, but allows you to specify
51 the input record separator in a coroutine-safe manner (i.e. not
52 using a global variable). Paragraph mode is not supported, use
53 "\n\n" to achieve the same effect.
54 $fh->autoflush ([...])
56 Always returns true, arguments are being ignored (exists for
57 compatibility only). Might change in the future.
58 $fh->fileno, $fh->close, $fh->read, $fh->sysread, $fh->syswrite,
60 $fh->print, $fh->printf
61 Work like their function equivalents (except read, which works like
62 sysread. You should not use the read function with Coro::Handle's,
63 it will work but it's not efficient).
64 connect, listen, bind, getsockopt, setsockopt, send, recv, peername,
66 sockname, shutdown, peerport, peerhost
67 Do the same thing as the perl builtins or IO::Socket methods (but
68 return true on EINPROGRESS). Remember that these must be method
69 calls.
70 peeraddr, peerhost, peerport
72 Return the peer host (as numericla IP address) and peer port (as
73 integer).
74 ($fh, $peername) = $listen_fh->accept
76 In scalar context, returns the newly accepted socket (or undef) and
77 in list context return the ($fh, $peername) pair (or nothing).
78 $fh->timeout ([...])
80 The optional argument sets the new timeout (in seconds) for this
81 handle. Returns the current (new) value.
82 0 is a valid timeout, use "undef" to disable the timeout.
84 $fh->fh
86 Returns the "real" (non-blocking) filehandle. Use this if you want
87 to do operations on the file handle you cannot do using the
88 Coro::Handle interface.
89 $fh->rbuf
91 Returns the current contents of the read buffer (this is an lvalue,
92 so you can change the read buffer if you like).
93 You can use this function to implement your own optimized reader
95 when neither readline nor sysread are viable candidates, like this:
96 # first get the _real_ non-blocking filehandle
98 # and fetch a reference to the read buffer
99 my $nb_fh = $fh->fh;
100 my $buf = \$fh->rbuf;
101 while () {
103 # now use buffer contents, modifying
104 # if necessary to reflect the removed data
105 last if $$buf ne ""; # we have leftover data
107 # read another buffer full of data
109 $fh->readable or die "end of file";
110 sysread $nb_fh, $$buf, 8192;
111 }
112
114 - Perl's IO-Handle model is THE bug.
115
117 Marc A. Lehmann <schmorp@schmorp.de>
118 http://software.schmorp.de/pkg/Coro.html
119perl v5.34.0 2021-07-22 Handle(3)