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



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 quali-
       fied by its containing Package) includes its type character(s) at the beginning where pos-
       sible. 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 let-
       ters) where that object is used in some way.  Simple uses aren't preceded by a code let-
       ter. 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 "&".  Subrou-
       tine 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 pro-
               gram.

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, .



perl v5.8.8                                 2001-09-21                                 B::Xref(3)