BAP Online Manuals : Library Reference : Library by Name : fail
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6.2.49. fail

always fails

SYNOPSIS

fail
!,fail

SYNTAX

 fail

ARGUMENTS

(none)

DESCRIPTION

This is a standard PROLOG predicate. It never succeeds, thus causes backtracking to start. Fail may be used to program endless loops, or in combination with ' ! (cut) ' causes a predicate to definitely fail.

EXAMPLE

member(X,[a,b,c]),
	write(X),nl,
	fail.

member(X,[a,b,c,ende,d,e]),
	write(X),nl,
	X = ende,!,fail.

ERRORS

No runtime errors.

LAYERS

prolog-process, client-server, object

RELATED PREDICATES

! , true


BAP Online Manuals : Library Reference : Library by Name : fail
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