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CentOS 7.0 - man page for devel::stacktrace (centos section 3)

Devel::StackTrace(3)	       User Contributed Perl Documentation	     Devel::StackTrace(3)

NAME
       Devel::StackTrace - An object representing a stack trace

VERSION
       version 1.30

SYNOPSIS
	 use Devel::StackTrace;

	 my $trace = Devel::StackTrace->new;

	 print $trace->as_string; # like carp

	 # from top (most recent) of stack to bottom.
	 while (my $frame = $trace->next_frame) {
	     print "Has args\n" if $frame->hasargs;
	 }

	 # from bottom (least recent) of stack to top.
	 while (my $frame = $trace->prev_frame) {
	     print "Sub: ", $frame->subroutine, "\n";
	 }

DESCRIPTION
       The Devel::StackTrace module contains two classes, Devel::StackTrace and
       Devel::StackTrace::Frame.  The goal of this object is to encapsulate the information that
       can found through using the caller() function, as well as providing a simple interface to
       this data.

       The Devel::StackTrace object contains a set of Devel::StackTrace::Frame objects, one for
       each level of the stack.  The frames contain all the data available from "caller()".

       This code was created to support my Exception::Class::Base class (part of
       Exception::Class) but may be useful in other contexts.

'TOP' AND 'BOTTOM' OF THE STACK
       When describing the methods of the trace object, I use the words 'top' and 'bottom'.  In
       this context, the 'top' frame on the stack is the most recent frame and the 'bottom' is
       the least recent.

       Here's an example:

	 foo();  # bottom frame is here

	 sub foo {
	    bar();
	 }

	 sub bar {
	    Devel::StackTrace->new;  # top frame is here.
	 }

Devel::StackTrace METHODS
       o   Devel::StackTrace->new(%named_params)

	   Returns a new Devel::StackTrace object.

	   Takes the following parameters:

	   o	   frame_filter => $sub

		   By default, Devel::StackTrace will include all stack frames before the call to
		   its its constructor.

		   However, you may want to filter out some frames with more granularity than
		   'ignore_package' or 'ignore_class' allow.

		   You can provide a subroutine which is called with the raw frame data for each
		   frame. This is a hash reference with two keys, "caller", and "args", both of
		   which are array references. The "caller" key is the raw data as returned by
		   Perl's "caller()" function, and the "args" key are the subroutine arguments
		   found in @DB::args.

		   The filter should return true if the frame should be included, or false if it
		   should be skipped.

	   o	   ignore_package => $package_name OR \@package_names

		   Any frames where the package is one of these packages will not be on the
		   stack.

	   o	   ignore_class => $package_name OR \@package_names

		   Any frames where the package is a subclass of one of these packages (or is the
		   same package) will not be on the stack.

		   Devel::StackTrace internally adds itself to the 'ignore_package' parameter,
		   meaning that the Devel::StackTrace package is ALWAYS ignored.  However, if you
		   create a subclass of Devel::StackTrace it will not be ignored.

	   o	   no_refs => $boolean

		   If this parameter is true, then Devel::StackTrace will not store references
		   internally when generating stacktrace frames.  This lets your objects go out
		   of scope.

		   Devel::StackTrace replaces any references with their stringified
		   representation.

	   o	   no_args => $boolean

		   If this parameter is true, then Devel::StackTrace will not store caller
		   arguments in stack trace frames at all.

	   o	   respect_overload => $boolean

		   By default, Devel::StackTrace will call "overload::AddrRef()" to get the
		   underlying string representation of an object, instead of respecting the
		   object's stringification overloading.  If you would prefer to see the
		   overloaded representation of objects in stack traces, then set this parameter
		   to true.

	   o	   max_arg_length => $integer

		   By default, Devel::StackTrace will display the entire argument for each
		   subroutine call. Setting this parameter causes truncates each subroutine
		   argument's string representation if it is longer than this number of
		   characters.

	   o	   message => $string

		   By default, Devel::StackTrace will use 'Trace begun' as the message for the
		   first stack frame when you call "as_string". You can supply an alternative
		   message using this option.

	   o	   indent => $boolean

		   If this parameter is true, each stack frame after the first will start with a
		   tab character, just like "Carp::confess()".

       o   $trace->next_frame

	   Returns the next Devel::StackTrace::Frame object down on the stack.	If it hasn't been
	   called before it returns the first frame.  It returns undef when it reaches the bottom
	   of the stack and then resets its pointer so the next call to "next_frame" or
	   "prev_frame" will work properly.

       o   $trace->prev_frame

	   Returns the next Devel::StackTrace::Frame object up on the stack.  If it hasn't been
	   called before it returns the last frame.  It returns undef when it reaches the top of
	   the stack and then resets its pointer so pointer so the next call to "next_frame" or
	   "prev_frame" will work properly.

       o   $trace->reset_pointer

	   Resets the pointer so that the next call "next_frame" or "prev_frame" will start at
	   the top or bottom of the stack, as appropriate.

       o   $trace->frames

	   When this method is called with no arguments, it returns a list of
	   Devel::StackTrace::Frame objects. They are returned in order from top (most recent) to
	   bottom.

	   This method can also be used to set the object's frames if you pass it a list of
	   Devel::StackTrace::Frame objects objects.

	   This is useful if you want to filter the list of frames in ways that are more complex
	   than can be handled by "filter_frames":

	     $stacktrace->frames( my_filter( $stacktrace->frames() ) );

       o   $trace->frame ($index)

	   Given an index, returns the relevant frame or undef if there is not frame at that
	   index.  The index is exactly like a Perl array.  The first frame is 0 and negative
	   indexes are allowed.

       o   $trace->frame_count

	   Returns the number of frames in the trace object.

       o   $trace->as_string(\%p)

	   Calls as_string on each frame from top to bottom, producing output quite similar to
	   the Carp module's cluck/confess methods.

	   The optional "\%p" parameter only has one useful option. The "max_arg_length"
	   parameter truncates each subroutine argument's string representation if it is longer
	   than this number of characters.

SUPPORT
       Please submit bugs to the CPAN RT system at
       http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Devel%3A%3AStackTrace or via email at
       bug-devel-stacktrace@rt.cpan.org.

AUTHOR
       Dave Rolsky <autarch@urth.org>

COPYRIGHT AND LICENSE
       This software is Copyright (c) 2012 by Dave Rolsky.

       This is free software, licensed under:

	 The Artistic License 2.0 (GPL Compatible)

perl v5.16.3				    2012-11-20			     Devel::StackTrace(3)


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