NAME

       Debug::Trace - Perl extension to trace subroutine calls

SYNOPSIS

         perl -MDebug::Trace=foo,bar yourprogram.pl

DESCRIPTION

       Debug::Trace instruments subroutines to provide tracing information upon every call and
       return.

       Using Debug::Trace does not require any changes to your sources. Most often, it will be
       used from the command line:

         perl -MDebug::Trace=foo,bar yourprogram.pl

       This will have your subroutines foo() and bar() printing call and return information.

       Subroutine names may be fully qualified to denote subroutines in other packages than the
       default main::.

       By default, the trace information is output using the standard warn() function.

   MODIFIERS
       Modifiers can be inserted in the list of subroutines to change the default behavior of
       this module. All modifiers can be used in three ways:

       •   ":"name to enable a specific feature.

       •   ":no"name to disable a specific feature.

       •   ":"name"("value")" to set a feature to a specific value. In general, ":"name is
           equivalent to ":"name"(1)", while ":no"name corresponds to ":"name"(0)".

       The following modifiers are recognized:

       :warn
           Uses warn() to produce the trace output (default). ":nowarn" Sends trace output
           directly to STDERR.

       :caller
           Add basic call information to the trace message, including from where the routine was
           called, and by whom. This is enabled by default.

       :stacktrace
           Add a stack trace (call history).

       :maxlen(length)
           Truncate the length of the lines of trace information to length characters.

       The following modifiers can be used to control the way Data::Dumper prints the values of
       parameters and return values. See also Data::Dumper.

       :indent
           Controls the style of indentation. It can be set to 0, 1, 2 or 3.  Style 0 spews
           output without any newlines, indentation, or spaces between list items. :indent(0) is
           the default.

       :useqq
           When enabled, uses double quotes for representing string values.  Whitespace other
           than space will be represented as "[\n\t\r]", "unsafe" characters will be backslashed,
           and unprintable characters will be output as quoted octal integers. This is the
           default, use ":nouseqq" to disable.

       :maxdepth(depth)
           Can be set to a positive integer that specifies the depth beyond which which we don't
           print structure contents. The default is 2, which means one level of array/hashes in
           argument lists and return values is expanded.  If you use ":nomaxdepth" or
           :maxdepth(0), nested structures are fully expanded.

       :quotekeys
           Controls wether hash keys are always printed quoted. The default is ":noquotekeys".

       sortkeys
           Controls whether hash keys are dumped in sorted order. The default is ":nosortkeys".

       Modifiers apply only to the subroutines that follow in the list of arguments.

METHODS

       None, actually. Everything is handled by the module's import.

ENVIRONMENT VARIABLES

       Environment variable "PERL5DEBUGTRACE" can be used to preset initial modifiers, e.g.:

           export PERL5DEBUGTRACE=":warn:indent(2):nomaxdepth:quotekeys"

SEE ALSO

       Data::Dumper, Carp

AUTHOR

       Jan-Pieter Cornet <jpc@cpan.org>; Jos Boumans <kane@cpan.org>; Johan Vromans
       <jv@cpan.org>;

       This is an Amsterdam.pm production. See http://amsterdam.pm.org.

       Current maintainer is Johan Vromans <jv@cpan.org>.

COPYRIGHT

       Copyright 2002,2013 Amsterdam.pm. All rights reserved.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.