IO::Async::Debug(3pm) User Contributed Perl DocumentationIO::Async::Debug(3pm)
NAME
"IO::Async::Debug" - debugging control and support for IO::Async
DESCRIPTION
The following methods and behaviours are still experimental and may
change or even be removed in future.
Debugging support is enabled by an environment variable called
"IO_ASYNC_DEBUG" having a true value.
When debugging is enabled, the "make_event_cb" and "invoke_event"
methods on IO::Async::Notifier (and their "maybe_" variants) are
altered such that when the event is fired, a debugging line is printed,
using the "debug_printf" method. This identifes the name of the event.
By default, the line is only printed if the caller of one of these
methods is the same package as the object is blessed into, allowing it
to print the events of the most-derived class, without the extra
verbosity of the lower-level events of its parent class used to create
it. All calls regardless of caller can be printed by setting a number
greater than 1 as the value of "IO_ASYNC_DEBUG".
By default the debugging log goes to "STDERR", but two other
environment variables can redirect it. If "IO_ASYNC_DEBUG_FILE" is set,
it names a file which will be opened for writing, and logging written
into it. Otherwise, if "IO_ASYNC_DEBUG_FD" is set, it gives a file
descriptor number that logging should be written to. If opening the
named file or file descriptor fails then the log will be written to
"STDERR" as normal.
Extra debugging flags can be set in a comma-separated list in an
environment variable called "IO_ASYNC_DEBUG_FLAGS". The presence of
these flags can cause extra information to be written to the log. Full
details on these flags will be documented by the implementing classes.
Typically these flags take the form of one or more capital letters
indicating the class, followed by one or more lowercase letters
enabling some particular feature within that class.
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.34.0 2022-08-19 IO::Async::Debug(3pm)
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