For a class of scalar fields including the massless Klein-Gordon field
the general relativistic hyperboloidal initial-value problems are equ
ivalent in a certain sense. By using this equivalence and conformal te
chniques it is proved that the hyperboloidal initial-value problem for
these scalar-fields has a unique solution which is weakly asymptotica
lly flat. For data sufficiently close to data for flat spacetime there
exists a smooth future null infinity and a regular future timelike in
finity.