11.3.146 once/1   ISO

Synopsis

once(+P)

Equivalent to:

call(P) -> true ; fail.

except that the use of call/1 often can be avoided.

Arguments

:P

callable, must be nonvar

Cuts in P do not make sense, but are allowed, their scope being the goal P.

Exceptions

Call errors (see ref-sem-exc).

See Also

ref-sem.