For a function f(z) belonging to a class A of normalized analytic functions in the unit disc, we define the generalized Libera integral operator by
The operator , when , was introduced by S. D. Bernardi [Trans. Am. Math. Soc. 135, 429-446 (1969; Zbl 0172.097)]. In particular, the operator was studied earlier by R. J. Libera [Proc. Am. Math. Soc. 16, 755-758 (1965; Zbl 0158.077)] and A. E. Livingston [Proc. Am. Math. Soc. 17, 352-357 (1966; Zbl 0158.077)].
The object of the present paper is to prove several interesting characterization theorems involving the generalized Libera integral operator and a general class C(, of close-to- convex functions in the unit disc. An application of the integral operator to a class of generalized hypergeometric functions is also considered.