


ext::B::B::Xref(3Perl Programmers Reference Guext::B::B::Xref(3p)


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



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ext::B::B::Xref(3Perl Programmers Reference Guext::B::B::Xref(3p)


               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, mbeattie@sable.ox.ac.uk.


































perl v5.10.1                2009-10-12                          2


