[ViewVC] Diff of: cvs/AnyEvent/README

Comparing AnyEvent/README (file contents):
Revision 1.68 by root, Fri Aug 26 18:09:04 2011 UTC vs.
Revision 1.69 by root, Tue Oct 4 17:45:04 2011 UTC

     will not restart syscalls (that includes Async::Interrupt and AnyEvent's
     pure perl implementation).
    Safe/Unsafe Signals
     Perl signals can be either "safe" (synchronous to opcode handling) or
-    "unsafe" (asynchronous) - the former might get delayed indefinitely, the
+    "unsafe" (asynchronous) - the former might delay signal delivery
-    latter might corrupt your memory.
+    indefinitely, the latter might corrupt your memory.
     AnyEvent signal handlers are, in addition, synchronous to the event
     loop, i.e. they will not interrupt your running perl program but will
     only be called as part of the normal event handling (just like timer,
     I/O etc. callbacks, too).
    Signal Races, Delays and Workarounds
     Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
     callbacks to signals in a generic way, which is a pity, as you cannot do
     race-free signal handling in perl, requiring C libraries for this.
     AnyEvent will try to do its best, which means in some cases, signals
-    will be delayed. The maximum time a signal might be delayed is specified
+    will be delayed. The maximum time a signal might be delayed is 10
-    in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable
+    seconds by default, but can be overriden via
-    can be changed only before the first signal watcher is created, and
+    $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY
-    should be left alone otherwise. This variable determines how often
+    - see the Ö<ENVIRONMENT VARIABLES> section for details.
-    AnyEvent polls for signals (in case a wake-up was missed). Higher values
-    will cause fewer spurious wake-ups, which is better for power and CPU
-    saving.
     All these problems can be avoided by installing the optional
     Async::Interrupt module, which works with most event loops. It will not
     work with inherently broken event loops such as Event or Event::Lib (and
-    not with POE currently, as POE does its own workaround with one-second
-    latency). For those, you just have to suffer the delays.
+    not with POE currently). For those, you just have to suffer the delays.
   CHILD PROCESS WATCHERS
        $w = AnyEvent->child (pid => <process id>, cb => <callback>);
     You can also watch for a child process exit and catch its exit status.
         If AnyEvent::Log is not loaded then this function makes a simple
         test to see whether the message will be logged. If the test succeeds
         it will load AnyEvent::Log and call "AnyEvent::Log::log" -
         consequently, look at the AnyEvent::Log documentation for details.
-        If the test fails it will simply return.
+        If the test fails it will simply return. Right now this happens when
+        a numerical loglevel is used and it is larger than the level
+        specified via $ENV{PERL_ANYEVENT_VERBOSE}.
         If you want to sprinkle loads of logging calls around your code,
         consider creating a logger callback with the "AnyEvent::Log::logger"
         function, which can reduce typing, codesize and can reduce the
         logging overhead enourmously.
     This ensures that child processes will not see the "AE_" variables.
     The following environment variables are currently known to AnyEvent:
     "PERL_ANYEVENT_VERBOSE"
-        By default, AnyEvent will be completely silent except in fatal
+        By default, AnyEvent will only log messages with loglevel 3
-        conditions. You can set this environment variable to make AnyEvent
+        ("critical") or higher (see AnyEvent::Log). You can set this
-        more talkative. If you want to do more than just set the global
+        environment variable to a numerical loglevel to make AnyEvent more
+        (or less) talkative.
+        If you want to do more than just set the global logging level you
-        logging level you should have a look at "PERL_ANYEVENT_LOG", which
+        should have a look at "PERL_ANYEVENT_LOG", which allows much more
-        allows much more complex specifications.
+        complex specifications.
+        When set to 0 ("off"), then no messages whatsoever will be logged
+        with the default logging settings.
-        When set to 5 or higher (warn), causes AnyEvent to warn about
+        When set to 5 or higher ("warn"), causes AnyEvent to warn about
         unexpected conditions, such as not being able to load the event
         model specified by "PERL_ANYEVENT_MODEL", or a guard callback
         throwing an exception - this is the minimum recommended level.
         When set to 7 or higher (info), cause AnyEvent to report which event
         is definitely recommended to keep it off in production. Keeping
         "PERL_ANYEVENT_STRICT=1" in your environment while developing
         programs can be very useful, however.
     "PERL_ANYEVENT_DEBUG_SHELL"
-        If this env variable is set, then its contents will be interpreted
+        If this env variable is nonempty, then its contents will be
-        by "AnyEvent::Socket::parse_hostport" (after replacing every
+        interpreted by "AnyEvent::Socket::parse_hostport" and
-        occurance of $$ by the process pid) and an "AnyEvent::Debug::shell"
+        "AnyEvent::Debug::shell" (after replacing every occurance of $$ by
-        is bound on that port. The shell object is saved in
+        the process pid). The shell object is saved in
         $AnyEvent::Debug::SHELL.
         This happens when the first watcher is created.
         For example, to bind a debug shell on a unix domain socket in
         /tmp/debug<pid>.sock, you could use this:
            PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
+           # connect with e.g.: socat readline /tmp/debug123.sock
+        Or to bind to tcp port 4545 on localhost:
+           PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
+           # connect with e.g.: telnet localhost 4545
-        Note that creating sockets in /tmp is very unsafe on multiuser
+        Note that creating sockets in /tmp or on localhost is very unsafe on
-        systems.
+        multiuser systems.
     "PERL_ANYEVENT_DEBUG_WRAP"
         Can be set to 0, 1 or 2 and enables wrapping of all watchers for
         debugging purposes. See "AnyEvent::Debug::wrap" for details.
     "PERL_ANYEVENT_MAX_OUTSTANDING_DNS"
         The default value for the "max_outstanding" parameter for the
         default DNS resolver - this is the maximum number of parallel DNS
         requests that are sent to the DNS server.
+    "PERL_ANYEVENT_MAX_SIGNAL_LATENCY"
+        Perl has inherently racy signal handling (you can basically choose
+        between losing signals and memory corruption) - pure perl event
+        loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't
+        available) therefore have to poll regularly to avoid losing signals.
+        Some event loops are racy, but don't poll regularly, and some event
+        loops are written in C but are still racy. For those event loops,
+        AnyEvent installs a timer that regularly wakes up the event loop.
+        By default, the interval for this timer is 10 seconds, but you can
+        override this delay with this environment variable (or by setting
+        the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal
+        watchers).
+        Lower values increase CPU (and energy) usage, higher values can
+        introduce long delays when reaping children or waiting for signals.
+        The AnyEvent::Async module, if available, will be used to avoid this
+        polling (with most event loops).
     "PERL_ANYEVENT_RESOLV_CONF"
         The absolute path to a resolv.conf-style file to use instead of
         /etc/resolv.conf (or the OS-specific configuration) in the default
         resolver, or the empty string to select the default configuration.

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Comparing AnyEvent/README (file contents): Revision 1.68 by root, Fri Aug 26 18:09:04 2011 UTC vs. Revision 1.69 by root, Tue Oct 4 17:45:04 2011 UTC

Diff Legend

Comparing AnyEvent/README (file contents):
Revision 1.68 by root, Fri Aug 26 18:09:04 2011 UTC vs.
Revision 1.69 by root, Tue Oct 4 17:45:04 2011 UTC