| … | |
… | |
| 2076 | Signal watchers will trigger an event when the process receives a specific |
2076 | Signal watchers will trigger an event when the process receives a specific |
| 2077 | signal one or more times. Even though signals are very asynchronous, libev |
2077 | signal one or more times. Even though signals are very asynchronous, libev |
| 2078 | will try it's best to deliver signals synchronously, i.e. as part of the |
2078 | will try it's best to deliver signals synchronously, i.e. as part of the |
| 2079 | normal event processing, like any other event. |
2079 | normal event processing, like any other event. |
| 2080 | |
2080 | |
|
|
2081 | Note that only the default loop supports registering signal watchers |
|
|
2082 | currently. |
|
|
2083 | |
| 2081 | If you want signals asynchronously, just use C<sigaction> as you would |
2084 | If you want signals asynchronously, just use C<sigaction> as you would |
| 2082 | do without libev and forget about sharing the signal. You can even use |
2085 | do without libev and forget about sharing the signal. You can even use |
| 2083 | C<ev_async> from a signal handler to synchronously wake up an event loop. |
2086 | C<ev_async> from a signal handler to synchronously wake up an event loop. |
| 2084 | |
2087 | |
| 2085 | You can configure as many watchers as you like per signal. Only when the |
2088 | You can configure as many watchers as you like per signal. Only when the |
| 2086 | first watcher gets started will libev actually register a signal handler |
2089 | first watcher gets started will libev actually register something with |
| 2087 | with the kernel (thus it coexists with your own signal handlers as long as |
2090 | the kernel (thus it coexists with your own signal handlers as long as you |
| 2088 | you don't register any with libev for the same signal). Similarly, when |
2091 | don't register any with libev for the same signal). |
| 2089 | the last signal watcher for a signal is stopped, libev will reset the |
2092 | |
| 2090 | signal handler to SIG_DFL (regardless of what it was set to before). |
2093 | Both the signal mask state (C<sigprocmask>) and the signal handler state |
|
|
2094 | (C<sigaction>) are unspecified after starting a signal watcher (and after |
|
|
2095 | sotpping it again), that is, libev might or might not block the signal, |
|
|
2096 | and might or might not set or restore the installed signal handler. |
| 2091 | |
2097 | |
| 2092 | If possible and supported, libev will install its handlers with |
2098 | If possible and supported, libev will install its handlers with |
| 2093 | C<SA_RESTART> behaviour enabled, so system calls should not be unduly |
2099 | C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should |
| 2094 | interrupted. If you have a problem with system calls getting interrupted by |
2100 | not be unduly interrupted. If you have a problem with system calls getting |
| 2095 | signals you can block all signals in an C<ev_check> watcher and unblock |
2101 | interrupted by signals you can block all signals in an C<ev_check> watcher |
| 2096 | them in an C<ev_prepare> watcher. |
2102 | and unblock them in an C<ev_prepare> watcher. |
| 2097 | |
2103 | |
| 2098 | =head3 Watcher-Specific Functions and Data Members |
2104 | =head3 Watcher-Specific Functions and Data Members |
| 2099 | |
2105 | |
| 2100 | =over 4 |
2106 | =over 4 |
| 2101 | |
2107 | |
| … | |
… | |
| 2146 | libev) |
2152 | libev) |
| 2147 | |
2153 | |
| 2148 | =head3 Process Interaction |
2154 | =head3 Process Interaction |
| 2149 | |
2155 | |
| 2150 | Libev grabs C<SIGCHLD> as soon as the default event loop is |
2156 | Libev grabs C<SIGCHLD> as soon as the default event loop is |
| 2151 | initialised. This is necessary to guarantee proper behaviour even if |
2157 | initialised. This is necessary to guarantee proper behaviour even if the |
| 2152 | the first child watcher is started after the child exits. The occurrence |
2158 | first child watcher is started after the child exits. The occurrence |
| 2153 | of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
2159 | of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
| 2154 | synchronously as part of the event loop processing. Libev always reaps all |
2160 | synchronously as part of the event loop processing. Libev always reaps all |
| 2155 | children, even ones not watched. |
2161 | children, even ones not watched. |
| 2156 | |
2162 | |
| 2157 | =head3 Overriding the Built-In Processing |
2163 | =head3 Overriding the Built-In Processing |
| … | |
… | |
| 2167 | =head3 Stopping the Child Watcher |
2173 | =head3 Stopping the Child Watcher |
| 2168 | |
2174 | |
| 2169 | Currently, the child watcher never gets stopped, even when the |
2175 | Currently, the child watcher never gets stopped, even when the |
| 2170 | child terminates, so normally one needs to stop the watcher in the |
2176 | child terminates, so normally one needs to stop the watcher in the |
| 2171 | callback. Future versions of libev might stop the watcher automatically |
2177 | callback. Future versions of libev might stop the watcher automatically |
| 2172 | when a child exit is detected. |
2178 | when a child exit is detected (calling C<ev_child_stop> twice is not a |
|
|
2179 | problem). |
| 2173 | |
2180 | |
| 2174 | =head3 Watcher-Specific Functions and Data Members |
2181 | =head3 Watcher-Specific Functions and Data Members |
| 2175 | |
2182 | |
| 2176 | =over 4 |
2183 | =over 4 |
| 2177 | |
2184 | |
