Logtalk reference manual
Built-in predicate: create_protocol/3
Contents > Reference Manual > Built-in Predicates > create_protocol/3

## create_protocol/3

#### Description

    create_protocol(Identifier, Relations, Directives)

Creates a new, dynamic protocol. This predicate is often used as a primitive to implement high-level protocol creation methods.

When using Logtalk multi-threading features, predicates calling this built-in predicate may need to be declared synchronized in order to avoid race conditions.

#### Template and modes

    create_protocol(?protocol_identifier, +list, +list)

#### Errors

Either Relations or Directives is a variable:
  `instantiation_error`
Identifier is neither a variable nor a valid protocol identifier:
  `type_error(protocol_identifier, Identifier)`
Identifier is already in use:
  `permission_error(replace, category, Identifier)`
  `permission_error(replace, object, Identifier)`
  `permission_error(replace, protocol, Identifier)`
Relations is neither a variable nor a proper list:
  `type_error(list, Relations)`
Directives is neither a variable nor a proper list:
  `type_error(list, Directives)`

#### Examples

    | ?- create_protocol(
            logging,
            [extends(monitoring)],
            [public([log_file/1, log_on/0, log_off/0])]
         ).