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@ -1456,7 +1456,32 @@ Example: Try to exit cleanly on SIGINT and SIGTERM. |
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=head2 C<ev_child> - watch out for process status changes |
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Child watchers trigger when your process receives a SIGCHLD in response to |
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some child status changes (most typically when a child of yours dies). |
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some child status changes (most typically when a child of yours dies). It |
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is permissible to install a child watcher I<after> the child has been |
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forked (which implies it might have already exited), as long as the event |
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loop isn't entered (or is continued from a watcher). |
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Only the default event loop is capable of handling signals, and therefore |
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you can only rgeister child watchers in the default event loop. |
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=head3 Process Interaction |
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Libev grabs C<SIGCHLD> as soon as the default event loop is |
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initialised. This is necessary to guarantee proper behaviour even if |
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the first child watcher is started after the child exits. The occurance |
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of C<SIGCHLD> is recorded asynchronously, but child reaping is done |
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synchronously as part of the event loop processing. Libev always reaps all |
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children, even ones not watched. |
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=head3 Overriding the Built-In Processing |
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Libev offers no special support for overriding the built-in child |
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processing, but if your application collides with libev's default child |
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handler, you can override it easily by installing your own handler for |
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C<SIGCHLD> after initialising the default loop, and making sure the |
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default loop never gets destroyed. You are encouraged, however, to use an |
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event-based approach to child reaping and thus use libev's support for |
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that, so other libev users can use C<ev_child> watchers freely. |
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=head3 Watcher-Specific Functions and Data Members |
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@ -1490,6 +1515,35 @@ C<waitpid> and C<sys/wait.h> documentation for details). |
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=back |
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=head3 Examples |
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Example: C<fork()> a new process and install a child handler to wait for |
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its completion. |
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ev_child cw; |
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static void |
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child_cb (EV_P_ struct ev_child *w, int revents) |
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{ |
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ev_child_stop (EV_A_ w); |
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printf ("process %d exited with status %x\n", w->rpid, w->rstatus); |
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} |
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pid_t pid = fork (); |
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if (pid < 0) |
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// error |
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else if (pid == 0) |
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{ |
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// the forked child executes here |
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exit (1); |
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} |
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else |
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{ |
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ev_child_init (&cw, child_cb, pid, 0); |
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ev_child_start (EV_DEFAULT_ &cw); |
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} |
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=head2 C<ev_stat> - did the file attributes just change? |
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