Improving the dependability of computer systems is increasingly important as more and more of our lives depend on the availability of such systems. Wrapping dynamic link libraries is an effective approach for improving the reliability and security of computer software without source code access. In this paper we describe a flexible framework to generate a rich set of software wrappers for shared libraries. We describe the architecture of the wrapper generator, the problems of how to generate wrappers efficiently, and our solutions to these problems. Based on a set of properties declared for a function, the generator can create a variety of wrappers to suit the diverse requirements of application programs. Performance measurements indicate that the overhead of the generated wrappers is small. Keywords: wrappers, wrapper generator, software fault-tolerance, middleware, reliability, security.