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Comparing libev/ev.pod (file contents):
Revision 1.264 by root, Wed Aug 19 23:44:51 2009 UTC vs.
Revision 1.265 by root, Wed Aug 26 17:11:42 2009 UTC

… …
2108 2108
2109When the first watcher gets started will libev actually register something 2109When the first watcher gets started will libev actually register something
2110with the kernel (thus it coexists with your own signal handlers as long as 2110with the kernel (thus it coexists with your own signal handlers as long as
2111you don't register any with libev for the same signal). 2111you don't register any with libev for the same signal).
2112 2112
2113Both the signal mask state (C<sigprocmask>) and the signal handler state
2114(C<sigaction>) are unspecified after starting a signal watcher (and after
2115sotpping it again), that is, libev might or might not block the signal,
2116and might or might not set or restore the installed signal handler.
2117
2118If possible and supported, libev will install its handlers with 2113If possible and supported, libev will install its handlers with
2119C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should 2114C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
2120not be unduly interrupted. If you have a problem with system calls getting 2115not be unduly interrupted. If you have a problem with system calls getting
2121interrupted by signals you can block all signals in an C<ev_check> watcher 2116interrupted by signals you can block all signals in an C<ev_check> watcher
2122and unblock them in an C<ev_prepare> watcher. 2117and unblock them in an C<ev_prepare> watcher.
2118
2119=head3 The special problem of inheritance over execve
2120
2121Both the signal mask (C<sigprocmask>) and the signal disposition
2122(C<sigaction>) are unspecified after starting a signal watcher (and after
2123stopping it again), that is, libev might or might not block the signal,
2124and might or might not set or restore the installed signal handler.
2125
2126While this does not matter for the signal disposition (libev never
2127sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
2128C<execve>), this matters for the signal mask: many programs do not expect
2129many signals to be blocked.
2130
2131This means that before calling C<exec> (from the child) you should reset
2132the signal mask to whatever "default" you expect (all clear is a good
2133choice usually).
2123 2134
2124=head3 Watcher-Specific Functions and Data Members 2135=head3 Watcher-Specific Functions and Data Members
2125 2136
2126=over 4 2137=over 4
2127 2138

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