I have taken folloing from a post on this forum. Still I could not make out few things.

use vars qw/$x, @y, %z, $d, @e, %f, $p, @q, %r/;
 $a = 10;
 my ($b) ; # what is the meaning of bracket around variable name ?

{
  # ...
  my ($p, @q, %r); 
  local ($d, @e, %f);      # (1)
  # ...
  sub foo { # ...
  }
  # ...
  foo(17);               # (2)
  bar($p,29);            # (3)
  lbar($d, 31);
  # ...
}                        # (4)
# ...
sub bar { # ...
}

{
  # ...
  local ($x, @y, %z);     # (5)
  local $a = 20;
  my $a = 30;
  # ...
  sub baz { # ...
  }
  # ...
  baz(17);                # (6)
  quux($x,29);            # (7)
  # ...
  sub child {
  
  $b = a * 10; # which value of \$a will be available here ?
  
 }
}                         # (8)
# ...
sub quux { # ...
}
# ...
baz(29);                  # (9)

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1) Can global variable be declared anywhere in the code or only at the beginning of the code ?

2) If local variable and my variable both are declared using same name, is that allowed or is that an error ? If global variable and local variable , both have same name and I want to use global variable in the scope where my $a variable is declared, I can call it using $::a. In the child(), I have not declared $a and I want to call global value of $a in the child(). If I again use $::a, will it call the global value of $a or will it be value my $a ? If call $a in the child(), without using $::a, will it still call global value of $a or my $a declared in the scope in which child() is declared ?

3) If thats allowed, and in the sub(), if I am using variable name, which valkue will be taken in sub()

4) If a sub() is declared within a sub(), can the variables declared in super sub() be accessed in child sub() without being declared in child () ?

5) Declaring variables at the beginning of the code using "use vars", is it the only way to declare global variables ? or just declaring variables in the beginning of the code without local or my makes them global variables ?

6) what is the difference between my $b; and my ($b);

7) If my variable is declared to make its scope local, then whats the point in declaring my variable at the top level ? Like the "my ($b)" or my $c in this example ?

8) Is it true that my $p will not be available to bar() , as bar() is defined outside the scope of my ($p, @q, %r) and only global $p will be available ? But local $d will be available to lbar(), as lbar() is called within the in time scope of $d and it will not use global value of $d?

Please excuse me , if some questrions sound like repeated.

Thanks

In reply to Understanding difference between my and local variables. by manishrathi

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