Logtalk reference manual
Built-in predicate: set_logtalk_flag/2
Contents > Reference Manual > Built-in Predicates > set_logtalk_flag/2

## set_logtalk_flag/2

#### Description

    set_logtalk_flag(Flag, Value)

Sets Logtalk default, global, flag values. For local flag scope, use the corresponding `set_logtalk_flag/2` directive. To set a global flag value when compiling and loading a source file, wrap the calls to this built-in predicate with an `initialization/1` directive.

#### Template and modes

    set_logtalk_flag(+atom, +nonvar)

#### Errors

Flag is a variable:
  `instantiation_error`
Value is a variable:
  `instantiation_error`
Flag is not an atom:
  `type_error(atom, Flag)`
Flag is neither a variable nor a valid flag:
  `domain_error(flag, Flag)`
Value is not a valid value for flag Flag:
  `domain_error(flag_value, Flag + Value)`
Flag is a read-only flag:
  `permission_error(modify, flag, Flag)`

#### Examples

    | ?- set_logtalk_flag(unknown_entities, silent).