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

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

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

       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        C<line numbers>
                 object2        C<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

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

               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[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.

       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.

       Malcolm Beattie, mbeattie@sable.ox.ac.uk.

3rd Berkeley Distribution    perl 5.005, patch 02                   B::Xref(3)