Index for Section 3

Alphabetical listing for S

Bottom of page

Symbol(3)
NAME
  Symbol - manipulate Perl symbols and their names

SYNOPSIS
      use Symbol;

      $sym = gensym;
      open($sym, "filename");
      $_ = <$sym>;
      # etc.

      ungensym $sym;	  # no effect

      print qualify("x"), "\n";		     # "Test::x"
      print qualify("x", "FOO"), "\n"	     # "FOO::x"
      print qualify("BAR::x"), "\n";	     # "BAR::x"
      print qualify("BAR::x", "FOO"), "\n";  # "BAR::x"
      print qualify("STDOUT", "FOO"), "\n";  # "main::STDOUT" (global)
      print qualify(\*x), "\n";		     # returns \*x
      print qualify(\*x, "FOO"), "\n";	     # returns \*x

      use strict refs;
      print { qualify_to_ref $fh } "foo!\n";
      $ref = qualify_to_ref $name, $pkg;

      use Symbol qw(delete_package);
      delete_package('Foo::Bar');
      print "deleted\n" unless exists $Foo::{'Bar::'};

DESCRIPTION
  "Symbol::gensym" creates an anonymous glob and returns a reference to it.
  Such a glob reference can be used as a file or directory handle.

  For backward compatibility with older implementations that didn't support
  anonymous globs, "Symbol::ungensym" is also provided.	 But it doesn't do
  anything.

  "Symbol::qualify" turns unqualified symbol names into qualified variable
  names (e.g. "myvar" -> "MyPackage::myvar").  If it is given a second
  parameter, "qualify" uses it as the default package; otherwise, it uses the
  package of its caller.  Regardless, global variable names (e.g. "STDOUT",
  "ENV", "SIG") are always qualified with "main::".

  Qualification applies only to symbol names (strings).	 References are left
  unchanged under the assumption that they are glob references, which are
  qualified by their nature.

  "Symbol::qualify_to_ref" is just like "Symbol::qualify" except that it
  returns a glob ref rather than a symbol name, so you can use the result
  even if "use strict 'refs'" is in effect.

  "Symbol::delete_package" wipes out a whole package namespace.	 Note this
  routine is not exported by default--you may want to import it explicitly.

Index for Section 3

Alphabetical listing for S

Top of page