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 argument (apart from the special all and none options) is a word rep-
       resenting 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 exam-
               ple,

                   $foo = scalar(@bar);

       implicit-read and implicit-write
               These options produce a warning whenever an operation implicitly reads or (respec-
               tively) 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 anywhere 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 special 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 invoca-
               tions such as "&$subref()" or "$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, .



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