-extern void print_complex (cl_ostream stream, const cl_print_flags& flags, const cl_N& z);
-extern void print_complex (cl_ostream stream, const cl_print_number_flags& flags, const cl_N& z);
+extern void print_complex (std::ostream& stream, const cl_print_flags& flags, const cl_N& z);
+extern void print_complex (std::ostream& stream, const cl_print_number_flags& flags, const cl_N& z);