=encoding euc-jp

=head1 NAME

=begin original

autouse - postpone load of modules until a function is used

=end original

autouse - 関数が使われるまでモジュールの読み込みを延期する

=head1 SYNOPSIS

  use autouse 'Carp' => qw(carp croak);
  carp "this carp was predeclared and autoused ";

=head1 DESCRIPTION

=begin original

If the module C<Module> is already loaded, then the declaration

=end original

モジュール C<Module> が既に読み込まれていれば、以下の宣言は

  use autouse 'Module' => qw(func1 func2($;$));

=begin original

is equivalent to

=end original

以下と等価です

  use Module qw(func1 func2);

=begin original

if C<Module> defines func2() with prototype C<($;$)>, and func1() has
no prototypes.  (At least if C<Module> uses C<Exporter>'s C<import>,
otherwise it is a fatal error.)

=end original

C<Module> で、プロトタイプ C<($;$)> で func2() を、プロトタイプなしで
func1() を定義している場合です。
(少なくとも C<Module> が C<Exporter> の C<import> を使っている場合です;
さもなければ致命的エラーになります。)

=begin original

If the module C<Module> is not loaded yet, then the above declaration
declares functions func1() and func2() in the current package.  When
these functions are called, they load the package C<Module> if needed,
and substitute themselves with the correct definitions.

=end original

モジュール C<Module> がまだ読み込まれていない場合、上述の宣言は
現在のパッケージの関数 func1() と func2() を宣言します。
これらの関数が呼び出されると、必要ならパッケージが C<Module> が読み込まれ、
正しい定義と置き換えられます。

=begin _deprecated

   use Module qw(Module::func3);

will work and is the equivalent to:

   use Module qw(func3);

It is not a very useful feature and has been deprecated.

=end _deprecated

=head1 WARNING

=begin original

Using C<autouse> will move important steps of your program's execution
from compile time to runtime.  This can

=end original

Using C<autouse> will move important steps of your program's execution
from compile time to runtime.  This can
(TBT)

=over 4

=item *

=begin original

Break the execution of your program if the module you C<autouse>d has
some initialization which it expects to be done early.

=end original

Break the execution of your program if the module you C<autouse>d has
some initialization which it expects to be done early.
(TBT)

=item *

=begin original

hide bugs in your code since important checks (like correctness of
prototypes) is moved from compile time to runtime.  In particular, if
the prototype you specified on C<autouse> line is wrong, you will not
find it out until the corresponding function is executed.  This will be
very unfortunate for functions which are not always called (note that
for such functions C<autouse>ing gives biggest win, for a workaround
see below).

=end original

hide bugs in your code since important checks (like correctness of
prototypes) is moved from compile time to runtime.  In particular, if
the prototype you specified on C<autouse> line is wrong, you will not
find it out until the corresponding function is executed.  This will be
very unfortunate for functions which are not always called (note that
for such functions C<autouse>ing gives biggest win, for a workaround
see below).
(TBT)

=back

=begin original

To alleviate the second problem (partially) it is advised to write
your scripts like this:

=end original

To alleviate the second problem (partially) it is advised to write
your scripts like this:
(TBT)

  use Module;
  use autouse Module => qw(carp($) croak(&$));
  carp "this carp was predeclared and autoused ";

=begin original

The first line ensures that the errors in your argument specification
are found early.  When you ship your application you should comment
out the first line, since it makes the second one useless.

=end original

The first line ensures that the errors in your argument specification
are found early.  When you ship your application you should comment
out the first line, since it makes the second one useless.
(TBT)

=head1 AUTHOR

Ilya Zakharevich (ilya@math.ohio-state.edu)

=head1 SEE ALSO

perl(1).

=cut