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Revision 1.6 by root, Mon Jul 11 03:29:39 2005 UTC vs.
Revision 1.7 by root, Wed Jul 20 21:55:38 2005 UTC

… …
20 poll => 'r', 20 poll => 'r',
21 cb => \&IO::AIO::poll_cb); 21 cb => \&IO::AIO::poll_cb);
22 22
23 # Glib/Gtk2 23 # Glib/Gtk2
24 add_watch Glib::IO IO::AIO::poll_fileno, 24 add_watch Glib::IO IO::AIO::poll_fileno,
25 in => sub { IO::AIO::poll_cb, 1 }; 25 in => sub { IO::AIO::poll_cb; 1 };
26 26
27 # Tk 27 # Tk
28 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", 28 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
29 readable => \&IO::AIO::poll_cb); 29 readable => \&IO::AIO::poll_cb);
30 30
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45 currently, for example), and they would only support aio_read and 45 currently, for example), and they would only support aio_read and
46 aio_write, so the remaining functionality would have to be implemented 46 aio_write, so the remaining functionality would have to be implemented
47 using threads anyway. 47 using threads anyway.
48 48
49 Although the module will work with in the presence of other threads, it 49 Although the module will work with in the presence of other threads, it
50 is currently not reentrant, so use appropriate locking yourself. 50 is currently not reentrant, so use appropriate locking yourself, always
51 call "poll_cb" from within the same thread, or never call "poll_cb" (or
52 other "aio_" functions) recursively.
51 53
52FUNCTIONS 54FUNCTIONS
53 AIO FUNCTIONS 55 AIO FUNCTIONS
54 All the "aio_*" calls are more or less thin wrappers around the syscall 56 All the "aio_*" calls are more or less thin wrappers around the syscall
55 with the same name (sans "aio_"). The arguments are similar or 57 with the same name (sans "aio_"). The arguments are similar or
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61 63
62 All functions that expect a filehandle will also accept a file 64 All functions that expect a filehandle will also accept a file
63 descriptor. 65 descriptor.
64 66
65 The filenames you pass to these routines *must* be absolute. The reason 67 The filenames you pass to these routines *must* be absolute. The reason
66 is that at the time the request is being executed, the current working 68 for this is that at the time the request is being executed, the current
67 directory could have changed. Alternatively, you can make sure that you 69 working directory could have changed. Alternatively, you can make sure
68 never change the current working directory. 70 that you never change the current working directory.
69 71
70 aio_open $pathname, $flags, $mode, $callback 72 aio_open $pathname, $flags, $mode, $callback
71 Asynchronously open or create a file and call the callback with a 73 Asynchronously open or create a file and call the callback with a
72 newly created filehandle for the file. 74 newly created filehandle for the file.
73 75
74 The pathname passed to "aio_open" must be absolute. See API NOTES, 76 The pathname passed to "aio_open" must be absolute. See API NOTES,
75 above, for an explanation. 77 above, for an explanation.
76 78
77 The $mode argument is a bitmask. See the "Fcntl" module for a list. 79 The $flags argument is a bitmask. See the "Fcntl" module for a list.
78 They are the same as used in "sysopen". 80 They are the same as used by "sysopen".
81
82 Likewise, $mode specifies the mode of the newly created file, if it
83 didn't exist and "O_CREAT" has been given, just like perl's
84 "sysopen", except that it is mandatory (i.e. use 0 if you don't
85 create new files, and 0666 or 0777 if you do).
79 86
80 Example: 87 Example:
81 88
82 aio_open "/etc/passwd", O_RDONLY, 0, sub { 89 aio_open "/etc/passwd", O_RDONLY, 0, sub {
83 if ($_[0]) { 90 if ($_[0]) {
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90 97
91 aio_close $fh, $callback 98 aio_close $fh, $callback
92 Asynchronously close a file and call the callback with the result 99 Asynchronously close a file and call the callback with the result
93 code. *WARNING:* although accepted, you should not pass in a perl 100 code. *WARNING:* although accepted, you should not pass in a perl
94 filehandle here, as perl will likely close the file descriptor 101 filehandle here, as perl will likely close the file descriptor
95 itself when the filehandle is destroyed. Normally, you can safely 102 another time when the filehandle is destroyed. Normally, you can
96 call perls "close" or just let filehandles go out of scope. 103 safely call perls "close" or just let filehandles go out of scope.
104
105 This is supposed to be a bug in the API, so that might change. It's
106 therefore best to avoid this function.
97 107
98 aio_read $fh,$offset,$length, $data,$dataoffset,$callback 108 aio_read $fh,$offset,$length, $data,$dataoffset,$callback
99 aio_write $fh,$offset,$length, $data,$dataoffset,$callback 109 aio_write $fh,$offset,$length, $data,$dataoffset,$callback
100 Reads or writes "length" bytes from the specified "fh" and "offset" 110 Reads or writes "length" bytes from the specified "fh" and "offset"
101 into the scalar given by "data" and offset "dataoffset" and calls 111 into the scalar given by "data" and offset "dataoffset" and calls
… …
112 122
113 aio_readahead $fh,$offset,$length, $callback 123 aio_readahead $fh,$offset,$length, $callback
114 Asynchronously reads the specified byte range into the page cache, 124 Asynchronously reads the specified byte range into the page cache,
115 using the "readahead" syscall. If that syscall doesn't exist (likely 125 using the "readahead" syscall. If that syscall doesn't exist (likely
116 if your OS isn't Linux) the status will be -1 and $! is set to 126 if your OS isn't Linux) the status will be -1 and $! is set to
117 ENOSYS. 127 "ENOSYS".
118 128
119 readahead() populates the page cache with data from a file so that 129 "aio_readahead" populates the page cache with data from a file so
120 subsequent reads from that file will not block on disk I/O. The 130 that subsequent reads from that file will not block on disk I/O. The
121 $offset argument specifies the starting point from which data is to 131 $offset argument specifies the starting point from which data is to
122 be read and $length specifies the number of bytes to be read. I/O is 132 be read and $length specifies the number of bytes to be read. I/O is
123 performed in whole pages, so that offset is effectively rounded down 133 performed in whole pages, so that offset is effectively rounded down
124 to a page boundary and bytes are read up to the next page boundary 134 to a page boundary and bytes are read up to the next page boundary
125 greater than or equal to (off-set+length). aio_readahead() does not 135 greater than or equal to (off-set+length). "aio_readahead" does not
126 read beyond the end of the file. The current file offset of the file 136 read beyond the end of the file. The current file offset of the file
127 is left unchanged. 137 is left unchanged.
128 138
129 aio_stat $fh_or_path, $callback 139 aio_stat $fh_or_path, $callback
130 aio_lstat $fh, $callback 140 aio_lstat $fh, $callback
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155 Asynchronously call fsync on the given filehandle and call the 165 Asynchronously call fsync on the given filehandle and call the
156 callback with the fsync result code. 166 callback with the fsync result code.
157 167
158 aio_fdatasync $fh, $callback 168 aio_fdatasync $fh, $callback
159 Asynchronously call fdatasync on the given filehandle and call the 169 Asynchronously call fdatasync on the given filehandle and call the
160 callback with the fdatasync result code. 170 callback with the fdatasync result code. Might set $! to "ENOSYS" if
171 "fdatasync" is not available.
161 172
162 SUPPORT FUNCTIONS 173 SUPPORT FUNCTIONS
163 $fileno = IO::AIO::poll_fileno 174 $fileno = IO::AIO::poll_fileno
164 Return the *request result pipe filehandle*. This filehandle must be 175 Return the *request result pipe file descriptor*. This filehandle
165 polled for reading by some mechanism outside this module (e.g. Event 176 must be polled for reading by some mechanism outside this module
166 or select, see below). If the pipe becomes readable you have to call 177 (e.g. Event or select, see below or the SYNOPSIS). If the pipe
167 "poll_cb" to check the results. 178 becomes readable you have to call "poll_cb" to check the results.
168 179
169 See "poll_cb" for an example. 180 See "poll_cb" for an example.
170 181
171 IO::AIO::poll_cb 182 IO::AIO::poll_cb
172 Process all outstanding events on the result pipe. You have to call 183 Process all outstanding events on the result pipe. You have to call
173 this regularly. Returns the number of events processed. Returns 184 this regularly. Returns the number of events processed. Returns
174 immediately when no events are outstanding. 185 immediately when no events are outstanding.
175 186
176 You can use Event to multiplex, e.g.: 187 Example: Install an Event watcher that automatically calls
188 IO::AIO::poll_cb with high priority:
177 189
178 Event->io (fd => IO::AIO::poll_fileno, 190 Event->io (fd => IO::AIO::poll_fileno,
179 poll => 'r', async => 1, 191 poll => 'r', async => 1,
180 cb => \&IO::AIO::poll_cb); 192 cb => \&IO::AIO::poll_cb);
181 193
182 IO::AIO::poll_wait 194 IO::AIO::poll_wait
183 Wait till the result filehandle becomes ready for reading (simply 195 Wait till the result filehandle becomes ready for reading (simply
184 does a select on the filehandle. This is useful if you want to 196 does a "select" on the filehandle. This is useful if you want to
185 synchronously wait for some requests to finish). 197 synchronously wait for some requests to finish).
186 198
187 See "nreqs" for an example. 199 See "nreqs" for an example.
188 200
189 IO::AIO::nreqs 201 IO::AIO::nreqs
190 Returns the number of requests currently outstanding. 202 Returns the number of requests currently outstanding (i.e. for which
203 their callback has not been invoked yet).
191 204
192 Example: wait till there are no outstanding requests anymore: 205 Example: wait till there are no outstanding requests anymore:
193 206
194 IO::AIO::poll_wait, IO::AIO::poll_cb 207 IO::AIO::poll_wait, IO::AIO::poll_cb
195 while IO::AIO::nreqs; 208 while IO::AIO::nreqs;

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