The dlsym function returns the address of the symbol name found
    in the shareable image corresponding to handle. If the symbol is
    not found, a NULL pointer is returned.

    As of OpenVMS Version 7.3-2, library symbols containing
    lowercase characters can be loaded using the dlsym function. More
    generally, the functions that dynamically load libraries (dlopen,
    dlsym, dlclose, dlerror) are enhanced to provide the following
    capabilities:

    o  Support for libraries with mixed-case symbol names

    o  Ability to pass a full file path to dlopen

    o  Validation of the specified library name