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Revision 1.4 by root, Sun Jul 10 21:04:46 2005 UTC vs.
Revision 1.6 by root, Mon Jul 11 03:29:39 2005 UTC

1NAME 1NAME
2 IO::AIO - Asynchronous Input/Output 2 IO::AIO - Asynchronous Input/Output
3 3
4SYNOPSIS 4SYNOPSIS
5 use IO::AIO; 5 use IO::AIO;
6
7 aio_open "/etc/passwd", O_RDONLY, 0, sub {
8 my ($fh) = @_;
9 ...
10 };
11
12 aio_unlink "/tmp/file", sub { };
13
14 aio_read $fh, 30000, 1024, $buffer, 0, sub {
15 $_[0] > 0 or die "read error: $!";
16 };
17
18 # Event
19 Event->io (fd => IO::AIO::poll_fileno,
20 poll => 'r',
21 cb => \&IO::AIO::poll_cb);
22
23 # Glib/Gtk2
24 add_watch Glib::IO IO::AIO::poll_fileno,
25 in => sub { IO::AIO::poll_cb, 1 };
26
27 # Tk
28 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
29 readable => \&IO::AIO::poll_cb);
30
31 # Danga::Socket
32 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
33 \&IO::AIO::poll_cb);
6 34
7DESCRIPTION 35DESCRIPTION
8 This module implements asynchronous I/O using whatever means your 36 This module implements asynchronous I/O using whatever means your
9 operating system supports. 37 operating system supports.
10 38
… …
23 51
24FUNCTIONS 52FUNCTIONS
25 AIO FUNCTIONS 53 AIO FUNCTIONS
26 All the "aio_*" calls are more or less thin wrappers around the syscall 54 All the "aio_*" calls are more or less thin wrappers around the syscall
27 with the same name (sans "aio_"). The arguments are similar or 55 with the same name (sans "aio_"). The arguments are similar or
28 identical, and they all accept an additional $callback argument which 56 identical, and they all accept an additional (and optional) $callback
29 must be a code reference. This code reference will get called with the 57 argument which must be a code reference. This code reference will get
30 syscall return code (e.g. most syscalls return -1 on error, unlike perl, 58 called with the syscall return code (e.g. most syscalls return -1 on
31 which usually delivers "false") as it's sole argument when the given 59 error, unlike perl, which usually delivers "false") as it's sole
32 syscall has been executed asynchronously. 60 argument when the given syscall has been executed asynchronously.
33 61
34 All functions that expect a filehandle will also accept a file 62 All functions that expect a filehandle will also accept a file
35 descriptor. 63 descriptor.
36 64
37 The filenames you pass to these routines *must* be absolute. The reason 65 The filenames you pass to these routines *must* be absolute. The reason
… …
72 Reads or writes "length" bytes from the specified "fh" and "offset" 100 Reads or writes "length" bytes from the specified "fh" and "offset"
73 into the scalar given by "data" and offset "dataoffset" and calls 101 into the scalar given by "data" and offset "dataoffset" and calls
74 the callback without the actual number of bytes read (or -1 on 102 the callback without the actual number of bytes read (or -1 on
75 error, just like the syscall). 103 error, just like the syscall).
76 104
77 Example: Read 15 bytes at offset 7 into scalar $buffer, strating at 105 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at
78 offset 0 within the scalar: 106 offset 0 within the scalar:
79 107
80 aio_read $fh, 7, 15, $buffer, 0, sub { 108 aio_read $fh, 7, 15, $buffer, 0, sub {
81 $_[0] >= 0 or die "read error: $!"; 109 $_[0] > 0 or die "read error: $!";
82 print "read <$buffer>\n"; 110 print "read $_[0] bytes: <$buffer>\n";
83 }; 111 };
84 112
85 aio_readahead $fh,$offset,$length, $callback 113 aio_readahead $fh,$offset,$length, $callback
86 Asynchronously reads the specified byte range into the page cache, 114 Asynchronously reads the specified byte range into the page cache,
87 using the "readahead" syscall. If that syscall doesn't exist the 115 using the "readahead" syscall. If that syscall doesn't exist (likely
88 status will be -1 and $! is set to ENOSYS. 116 if your OS isn't Linux) the status will be -1 and $! is set to
117 ENOSYS.
89 118
90 readahead() populates the page cache with data from a file so that 119 readahead() populates the page cache with data from a file so that
91 subsequent reads from that file will not block on disk I/O. The 120 subsequent reads from that file will not block on disk I/O. The
92 $offset argument specifies the starting point from which data is to 121 $offset argument specifies the starting point from which data is to
93 be read and $length specifies the number of bytes to be read. I/O is 122 be read and $length specifies the number of bytes to be read. I/O is
… …
163 Example: wait till there are no outstanding requests anymore: 192 Example: wait till there are no outstanding requests anymore:
164 193
165 IO::AIO::poll_wait, IO::AIO::poll_cb 194 IO::AIO::poll_wait, IO::AIO::poll_cb
166 while IO::AIO::nreqs; 195 while IO::AIO::nreqs;
167 196
197 IO::AIO::flush
198 Wait till all outstanding AIO requests have been handled.
199
200 Strictly equivalent to:
201
202 IO::AIO::poll_wait, IO::AIO::poll_cb
203 while IO::AIO::nreqs;
204
205 IO::AIO::poll
206 Waits until some requests have been handled.
207
208 Strictly equivalent to:
209
210 IO::AIO::poll_wait, IO::AIO::poll_cb
211 if IO::AIO::nreqs;
212
168 IO::AIO::min_parallel $nthreads 213 IO::AIO::min_parallel $nthreads
169 Set the minimum number of AIO threads to $nthreads. The default is 214 Set the minimum number of AIO threads to $nthreads. The default is
170 1, which means a single asynchronous operation can be done at one 215 1, which means a single asynchronous operation can be done at one
171 time (the number of outstanding operations, however, is unlimited). 216 time (the number of outstanding operations, however, is unlimited).
172 217

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