Perl Pocket Reference, 4th Edition

Chapter 29. Tying Variables

tie var, classname, [ list ]

Ties a variable to a class that will handle it. list is passed to the class constructor.

tied var

Returns a reference to the object underlying var, or undef if var is not tied to a class.

untie var

Breaks the binding between the variable and the class. Calls an UNTIE method if provided.

A class implementing a tied scalar should define the methods TIESCALAR, DESTROY, FETCH, and STORE.

A class implementing a tied ordinary array should define the methods TIEARRAY, CLEAR, DESTROY, EXTEND, FETCHSIZE, FETCH, POP, PUSH, SHIFT, SPLICE, STORESIZE, STORE, and UNSHIFT.

A class implementing a tied hash should define the methods TIEHASH, CLEAR, DELETE, DESTROY, EXISTS, FETCH, FIRSTKEY, NEXTKEY, and STORE.

A class implementing a tied filehandle should define the methods TIEHANDLE, CLOSE, DESTROY, GETC, PRINTF, PRINT, READLINE, READ, and WRITE.

Several base classes to implement tied variables are available in the standard libraries: Tie::Array, Tie::Handle, Tie::Hash, Tie::RefHash, and Tie::Scalar.

perltie.