$ perl -e'
   use feature qw( say );
   say 0+\$x;
   { local $x; say 0+\$x; }
   say 0+\$x;
'
94031376424552
94031376229560
94031376424552

##</code><code>##

$ perl -e'
   use feature qw( say );
   $x = 2;
   say 0+\$x;
   say $x;
   sub {
      local $x = 3;
      say 0+\$x;
      say $x;
      say $_[0];
   }->( $x );
   say 0+\$x;
   say $x;
'
94300947464040   Address of pre-local $x
2                Value of pre-local $x
94300947268840   Address of post-local $x
3                Value of post-local $x
2                Value of pre-local $x
94300947464040   $x is restored
2                Value of pre-local $x

##</code><code>##

$ perl -e'
   use feature qw( say );
   $! = 2;
   say 0+\$!;
   say 0+$!;
   sub {
      local $! = 3;
      say 0+\$!;
      say 0+$!;
      say 0+$_[0];
   }->( $! );
   say 0+\$!;
   say 0+$!;
'
93839899443048   Address of pre-local $!
2                Value of pre-local $! (aka value of errno)
93839899247848   Address of post-local $!
3                Value of post-local $! (aka value of errno)
3                Value of pre-local $! (aka value of errno)
93839899443048   $! is restored
3                Value of pre-local $! (aka value of errno)