use - load in a module at compile time


use Module LIST

use Module


Imports some semantics into the current package from the named module, generally by aliasing certain subroutine or variable names into your package. It is exactly equivalent to

BEGIN { require Module; import Module LIST; }

The BEGIN forces the require and import to happen at compile time. The require makes sure the module is loaded into memory if it hasn't been yet. The import is not a builtin--it's just an ordinary static method call into the ``Module'' package to tell the module to import the list of features back into the current package. The module can implement its import method any way it likes, though most modules just choose to derive their import method via inheritance from the Exporter class that is defined in the Exporter module. See Exporter.

If you don't want your namespace altered, explicitly supply an empty list:

use Module ();

That is exactly equivalent to

BEGIN { require Module; }

Because this is a wide-open interface, pragmas (compiler directives) are also implemented this way. Currently implemented pragmas are:

use integer; use diagnostics; use sigtrap qw(SEGV BUS); use strict qw(subs vars refs); use subs qw(afunc blurfl);

These pseudomodules import semantics into the current block scope, unlike ordinary modules, which import symbols into the current package (which are effective through the end of the file).

There's a corresponding ``no'' command that unimports meanings imported by use.

no integer; no strict 'refs';

See the perlmod manpage for a list of standard modules and pragmas.