| … | |
… | |
| 2151 | |
2151 | |
| 2152 | Another way to think about it (for the mathematically inclined) is that |
2152 | Another way to think about it (for the mathematically inclined) is that |
| 2153 | C<ev_periodic> will try to run the callback in this mode at the next possible |
2153 | C<ev_periodic> will try to run the callback in this mode at the next possible |
| 2154 | time where C<time = offset (mod interval)>, regardless of any time jumps. |
2154 | time where C<time = offset (mod interval)>, regardless of any time jumps. |
| 2155 | |
2155 | |
| 2156 | For numerical stability it is preferable that the C<offset> value is near |
2156 | The C<interval> I<MUST> be positive, and for numerical stability, the |
| 2157 | C<ev_now ()> (the current time), but there is no range requirement for |
2157 | interval value should be higher than C<1/8192> (which is around 100 |
| 2158 | this value, and in fact is often specified as zero. |
2158 | microseconds) and C<offset> should be higher than C<0> and should have |
|
|
2159 | at most a similar magnitude as the current time (say, within a factor of |
|
|
2160 | ten). Typical values for offset are, in fact, C<0> or something between |
|
|
2161 | C<0> and C<interval>, which is also the recommended range. |
| 2159 | |
2162 | |
| 2160 | Note also that there is an upper limit to how often a timer can fire (CPU |
2163 | Note also that there is an upper limit to how often a timer can fire (CPU |
| 2161 | speed for example), so if C<interval> is very small then timing stability |
2164 | speed for example), so if C<interval> is very small then timing stability |
| 2162 | will of course deteriorate. Libev itself tries to be exact to be about one |
2165 | will of course deteriorate. Libev itself tries to be exact to be about one |
| 2163 | millisecond (if the OS supports it and the machine is fast enough). |
2166 | millisecond (if the OS supports it and the machine is fast enough). |
| … | |
… | |
| 4204 | F<event.h> that are not directly supported by the libev core alone. |
4207 | F<event.h> that are not directly supported by the libev core alone. |
| 4205 | |
4208 | |
| 4206 | In standalone mode, libev will still try to automatically deduce the |
4209 | In standalone mode, libev will still try to automatically deduce the |
| 4207 | configuration, but has to be more conservative. |
4210 | configuration, but has to be more conservative. |
| 4208 | |
4211 | |
|
|
4212 | =item EV_USE_FLOOR |
|
|
4213 | |
|
|
4214 | If defined to be C<1>, libev will use the C<floor ()> function for its |
|
|
4215 | periodic reschedule calculations, otherwise libev will fall back on a |
|
|
4216 | portable (slower) implementation. If you enable this, you usually have to |
|
|
4217 | link against libm or something equivalent. Enabling this when the C<floor> |
|
|
4218 | function is not available will fail, so the safe default is to not enable |
|
|
4219 | this. |
|
|
4220 | |
| 4209 | =item EV_USE_MONOTONIC |
4221 | =item EV_USE_MONOTONIC |
| 4210 | |
4222 | |
| 4211 | If defined to be C<1>, libev will try to detect the availability of the |
4223 | If defined to be C<1>, libev will try to detect the availability of the |
| 4212 | monotonic clock option at both compile time and runtime. Otherwise no |
4224 | monotonic clock option at both compile time and runtime. Otherwise no |
| 4213 | use of the monotonic clock option will be attempted. If you enable this, |
4225 | use of the monotonic clock option will be attempted. If you enable this, |
