B::Xref(3pm)                                    Perl Programmers Reference Guide                                    B::Xref(3pm)



NAME
       B::Xref - Generates cross reference reports for Perl programs

SYNOPSIS
       perl -MO=Xref[,OPTIONS] foo.pl

DESCRIPTION
       The B::Xref module is used to generate a cross reference listing of all definitions and uses of variables, subroutines
       and formats in a Perl program.  It is implemented as a backend for the Perl compiler.

       The report generated is in the following format:

           File filename1
             Subroutine subname1
               Package package1
                 object1        line numbers
                 object2        line numbers
                 ...
               Package package2
               ...

       Each File section reports on a single file. Each Subroutine section reports on a single subroutine apart from the special
       cases "(definitions)" and "(main)". These report, respectively, on subroutine definitions found by the initial symbol
       table walk and on the main part of the program or module external to all subroutines.

       The report is then grouped by the Package of each variable, subroutine or format with the special case "(lexicals)"
       meaning lexical variables. Each object name (implicitly qualified by its containing Package) includes its type
       character(s) at the beginning where possible. Lexical variables are easier to track and even included dereferencing
       information where possible.

       The "line numbers" are a comma separated list of line numbers (some preceded by code letters) where that object is used
       in some way.  Simple uses aren't preceded by a code letter. Introductions (such as where a lexical is first defined with
       "my") are indicated with the letter "i". Subroutine and method calls are indicated by the character "&".  Subroutine
       definitions are indicated by "s" and format definitions by "f".

OPTIONS
       Option words are separated by commas (not whitespace) and follow the usual conventions of compiler backend options.

       "-oFILENAME"
               Directs output to "FILENAME" instead of standard output.

       "-r"    Raw output. Instead of producing a human-readable report, outputs a line in machine-readable form for each
               definition/use of a variable/sub/format.

       "-d"    Don't output the "(definitions)" sections.

       "-D[tO]"
               (Internal) debug options, probably only useful if "-r" included.  The "t" option prints the object on the top of
               the stack as it's being tracked. The "O" option prints each operator as it's being processed in the execution
               order of the program.

BUGS
       Non-lexical variables are quite difficult to track through a program.  Sometimes the type of a non-lexical variable's use
       is impossible to determine. Introductions of non-lexical non-scalars don't seem to be reported properly.

AUTHOR
       Malcolm Beattie, mbeattieATsable.uk.



perl v5.12.4                                               2011-06-01                                               B::Xref(3pm)