1IO::Async::Debug(3) User Contributed Perl Documentation IO::Async::Debug(3)
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6 "IO::Async::Debug" - debugging control and support for IO::Async
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9 The following methods and behaviours are still experimental and may
10 change or even be removed in future.
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12 Debugging support is enabled by an environment variable called
13 "IO_ASYNC_DEBUG" having a true value.
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15 When debugging is enabled, the "make_event_cb" and "invoke_event"
16 methods on IO::Async::Notifier (and their "maybe_" variants) are
17 altered such that when the event is fired, a debugging line is printed,
18 using the "debug_printf" method. This identifes the name of the event.
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20 By default, the line is only printed if the caller of one of these
21 methods is the same package as the object is blessed into, allowing it
22 to print the events of the most-derived class, without the extra
23 verbosity of the lower-level events of its parent class used to create
24 it. All calls regardless of caller can be printed by setting a number
25 greater than 1 as the value of "IO_ASYNC_DEBUG".
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27 By default the debugging log goes to "STDERR", but two other
28 environment variables can redirect it. If "IO_ASYNC_DEBUG_FILE" is set,
29 it names a file which will be opened for writing, and logging written
30 into it. Otherwise, if "IO_ASYNC_DEBUG_FD" is set, it gives a file
31 descriptor number that logging should be written to. If opening the
32 named file or file descriptor fails then the log will be written to
33 "STDERR" as normal.
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35 Extra debugging flags can be set in a comma-separated list in an
36 environment variable called "IO_ASYNC_DEBUG_FLAGS". The presence of
37 these flags can cause extra information to be written to the log. Full
38 details on these flags will be documented by the implementing classes.
39 Typically these flags take the form of one or more capital letters
40 indicating the class, followed by one or more lowercase letters
41 enabling some particular feature within that class.
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44 Paul Evans <leonerd@leonerd.org.uk>
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48perl v5.32.1 2021-01-27 IO::Async::Debug(3)