| … | |
… | |
| 148 | creates a watcher waiting for "r"eadable or "w"ritable events, |
148 | creates a watcher waiting for "r"eadable or "w"ritable events, |
| 149 | respectively. C<cb> is the callback to invoke each time the file handle |
149 | respectively. C<cb> is the callback to invoke each time the file handle |
| 150 | becomes ready. |
150 | becomes ready. |
| 151 | |
151 | |
| 152 | The I/O watcher might use the underlying file descriptor or a copy of it. |
152 | The I/O watcher might use the underlying file descriptor or a copy of it. |
| 153 | It is not allowed to close a file handle as long as any watcher is active |
153 | You must not close a file handle as long as any watcher is active on the |
| 154 | on the underlying file descriptor. |
154 | underlying file descriptor. |
| 155 | |
155 | |
| 156 | Some event loops issue spurious readyness notifications, so you should |
156 | Some event loops issue spurious readyness notifications, so you should |
| 157 | always use non-blocking calls when reading/writing from/to your file |
157 | always use non-blocking calls when reading/writing from/to your file |
| 158 | handles. |
158 | handles. |
|
|
159 | |
|
|
160 | Although the callback might get passed parameters, their value and |
|
|
161 | presence is undefined and you cannot rely on them. Portable AnyEvent |
|
|
162 | callbacks cannot use arguments passed to I/O watcher callbacks. |
| 159 | |
163 | |
| 160 | Example: |
164 | Example: |
| 161 | |
165 | |
| 162 | # wait for readability of STDIN, then read a line and disable the watcher |
166 | # wait for readability of STDIN, then read a line and disable the watcher |
| 163 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
167 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
| … | |
… | |
| 176 | case. |
180 | case. |
| 177 | |
181 | |
| 178 | The timer callback will be invoked at most once: if you want a repeating |
182 | The timer callback will be invoked at most once: if you want a repeating |
| 179 | timer you have to create a new watcher (this is a limitation by both Tk |
183 | timer you have to create a new watcher (this is a limitation by both Tk |
| 180 | and Glib). |
184 | and Glib). |
|
|
185 | |
|
|
186 | Although the callback might get passed parameters, their value and |
|
|
187 | presence is undefined and you cannot rely on them. Portable AnyEvent |
|
|
188 | callbacks cannot use arguments passed to time watcher callbacks. |
| 181 | |
189 | |
| 182 | Example: |
190 | Example: |
| 183 | |
191 | |
| 184 | # fire an event after 7.7 seconds |
192 | # fire an event after 7.7 seconds |
| 185 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
193 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
| … | |
… | |
| 946 | file descriptors grows high. In this benchmark, all events become ready at |
954 | file descriptors grows high. In this benchmark, all events become ready at |
| 947 | the same time, so select/poll-based implementations get an unnatural speed |
955 | the same time, so select/poll-based implementations get an unnatural speed |
| 948 | boost. |
956 | boost. |
| 949 | |
957 | |
| 950 | C<EV> is the sole leader regarding speed and memory use, which are both |
958 | C<EV> is the sole leader regarding speed and memory use, which are both |
| 951 | maximal/minimal, respectively. Even when going through AnyEvent, there are |
959 | maximal/minimal, respectively. Even when going through AnyEvent, it uses |
| 952 | only two event loops that use slightly less memory (the C<Event> module |
960 | far less memory than any other event loop and is still faster than Event |
| 953 | natively and the pure perl backend), and no faster event models, not even |
961 | natively. |
| 954 | C<Event> natively. |
|
|
| 955 | |
962 | |
| 956 | The pure perl implementation is hit in a few sweet spots (both the |
963 | The pure perl implementation is hit in a few sweet spots (both the |
| 957 | zero timeout and the use of a single fd hit optimisations in the perl |
964 | zero timeout and the use of a single fd hit optimisations in the perl |
| 958 | interpreter and the backend itself, and all watchers become ready at the |
965 | interpreter and the backend itself, and all watchers become ready at the |
| 959 | same time). Nevertheless this shows that it adds very little overhead in |
966 | same time). Nevertheless this shows that it adds very little overhead in |
