
\+ +Goal

   Succeeds if Goal cannot be satisfied.  Uses negation as failure (synonym of not/1).



Arguments
   Goal                Goal.

Type
   Control

Description
   Used to fail if the goal Goal can be satisfied.  Uses the standard
   Prolog form of negation as failure.


   May be used to check whether a call Goal succeeds without binding
   variables, the call \+ \+ Goal can be used.


   Note that:


   !/0 does not cut through \+/1.




Modes and Determinism
   \+(+) is semidet

Modules
   This predicate is sensitive to its module context (tool predicate, see @/2).

Fail Conditions
   Fails if Goal succeeds

Examples
   
Success:
      \+ fail.
      \+ 1 == 2.
      \+ X == 1.
      \+ \+ X = 1.
          % does not bind X
Fail:
      \+ X = 1.
      \+ true.
      \+ 3 == 3.





See Also
   -> / 2, not / 1, ~ / 1
