B::Lint

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



NAME
       B::Lint - Perl lint

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

DESCRIPTION
       The B::Lint module is equivalent to an extended version of the -w
       option of perl. It is named after the program lint which carries out a
       similar process for C programs.

OPTIONS AND LINT CHECKS
       Option words are separated by commas (not whitespace) and follow the
       usual conventions of compiler backend options. Following any options
       (indicated by a leading -) come lint check arguments. Each such argu-
       ment (apart from the special all and none options) is a word repre-
       senting one possible lint check (turning on that check) or is no-foo
       (turning off that check). Before processing the check arguments, a
       standard list of checks is turned on. Later options override earlier
       ones. Available options are:

       context Produces a warning whenever an array is used in an implicit
	       scalar context. For example, both of the lines

		   $foo = length(@bar);
		   $foo = @bar;

	       will elicit a warning. Using an explicit scalar() silences the
	       warning. For example,

		   $foo = scalar(@bar);

       implicit-read and implicit-write
	       These options produce a warning whenever an operation implic-
	       itly reads or (respectively) writes to one of Perl’s special
	       variables.  For example, implicit-read will warn about these:

		   /foo/;

	       and implicit-write will warn about these:

		   s/foo/bar/;

	       Both implicit-read and implicit-write warn about this:

		   for (@a) { ... }

       bare-subs
	       This option warns whenever a bareword is implicitly quoted,
	       but is also the name of a subroutine in the current package.
	       Typical mistakes that it will trap are:

		   use constant foo => ’bar’;
		   @a = ( foo => 1 );
		   $b{foo} = 2;

	       Neither of these will do what a naive user would expect.

       dollar-underscore
	       This option warns whenever $_ is used either explicitly any-
	       where or as the implicit argument of a print statement.

       private-names
	       This option warns on each use of any variable, subroutine or
	       method name that lives in a non-current package but begins
	       with an underscore ("_"). Warnings aren’t issued for the spe-
	       cial case of the single character name "_" by itself (e.g. $_
	       and @_).

       undefined-subs
	       This option warns whenever an undefined subroutine is invoked.
	       This option will only catch explicitly invoked subroutines
	       such as "foo()" and not indirect invocations such as "&$sub-
	       ref()" or "$obj->meth()". Note that some programs or modules
	       delay definition of subs until runtime by means of the
	       AUTOLOAD mechanism.

       regexp-variables
	       This option warns whenever one of the regexp variables $‘, $&
	       or $’ is used. Any occurrence of any of these variables in
	       your program can slow your whole program down. See perlre for
	       details.

       all     Turn all warnings on.

       none    Turn all warnings off.

NON LINT-CHECK OPTIONS
       -u Package
	       Normally, Lint only checks the main code of the program
	       together with all subs defined in package main. The -u option
	       lets you include other package names whose subs are then
	       checked by Lint.

BUGS
       This is only a very preliminary version.

       This module doesn’t work correctly on thread-enabled perls.

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



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