Check existing $^W functionality

__END__

# warnable code, warnings disabled

$a =+ 3 ;

EXPECT

########

-w

# warnable code, warnings enabled via command line switch

$a =+ 3 ;

EXPECT

Reversed += operator at - line 3.

Name "main::a" used only once: possible typo at - line 3.

########

#! perl -w

# warnable code, warnings enabled via #! line

$a =+ 3 ;

EXPECT

Reversed += operator at - line 3.

Name "main::a" used only once: possible typo at - line 3.

########

# warnable code, warnings enabled via compile time $^W

BEGIN { $^W = 1 }

$a =+ 3 ;

EXPECT

Reversed += operator at - line 4.

Name "main::a" used only once: possible typo at - line 4.

########

# compile-time warnable code, warnings enabled via runtime $^W

# so no warning printed.

$^W = 1 ;

$a =+ 3 ;

EXPECT

########

# warnable code, warnings enabled via runtime $^W

$^W = 1 ;

my $b ; chop $b ;

EXPECT

Use of uninitialized value in scalar chop at - line 4.

########

# warnings enabled at compile time, disabled at run time

BEGIN { $^W = 1 }

$^W = 0 ;

my $b ; chop $b ;

EXPECT

########

# warnings disabled at compile time, enabled at run time

BEGIN { $^W = 0 }

$^W = 1 ;

my $b ; chop $b ;

EXPECT

Use of uninitialized value in scalar chop at - line 5.

########

-w

--FILE-- abcd

my $b ; chop $b ;

1 ;

--FILE--

require "./abcd";

EXPECT

Use of uninitialized value in scalar chop at ./abcd line 1.

########

--FILE-- abcd

my $b ; chop $b ;

1 ;

--FILE--

#! perl -w

require "./abcd";

EXPECT

Use of uninitialized value in scalar chop at ./abcd line 1.

########

--FILE-- abcd

my $b ; chop $b ;

1 ;

--FILE--

$^W =1 ;

require "./abcd";

EXPECT

Use of uninitialized value in scalar chop at ./abcd line 1.

########

--FILE-- abcd

$^W = 0;

my $b ; chop $b ;

1 ;

--FILE--

$^W =1 ;

require "./abcd";

EXPECT

########

--FILE-- abcd

$^W = 1;

1 ;

--FILE--

$^W =0 ;

require "./abcd";

my $b ; chop $b ;

EXPECT

Use of uninitialized value in scalar chop at - line 3.

########

$^W = 1;

eval 'my $b ; chop $b ;' ;

print $@ ;

EXPECT

Use of uninitialized value in scalar chop at (eval 1) line 1.

########

eval '$^W = 1;' ;

print $@ ;

my $b ; chop $b ;

EXPECT

Use of uninitialized value in scalar chop at - line 4.

########

eval {$^W = 1;} ;

print $@ ;

my $b ; chop $b ;

EXPECT

Use of uninitialized value in scalar chop at - line 4.

########

{

local ($^W) = 1;

}

my $b ; chop $b ;

EXPECT

########

my $a ; chop $a ;

{

local ($^W) = 1;

my $b ; chop $b ;

}

my $c ; chop $c ;

EXPECT

Use of uninitialized value in scalar chop at - line 5.

########

-w

-e undef

EXPECT

Use of uninitialized value in -e at - line 2.

########

$^W = 1 + 2 ;

EXPECT

########

$^W = $a ;

EXPECT

########

sub fred {}

$^W = fred() ;

EXPECT

########

sub fred { my $b ; chop $b ;}

{ local $^W = 0 ;

fred() ;

}

EXPECT

########

sub fred { my $b ; chop $b ;}

{ local $^W = 1 ;

fred() ;

}

EXPECT

Use of uninitialized value in scalar chop at - line 2.