B::Xref

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 "(defini-
       tions)" and "(main)". These report, respectively, on subroutine defi-
       nitions 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 vari-
       ables. Each object name (implicitly qualified by its containing Pack-
       age) 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.	 Sim-
       ple 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 defini-
       tions 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, out-
	       puts 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 opera-
	       tor 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, mbeattie@sable.ox.ac.uk.



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