Directories may be specified as B . Any other names are treated as filenames to be searched for. Using arguments of the form C and C is recommended. See F for more information. An opaque 'library reference' is returned as a handle for the loaded object.
Returns undef on error.
This is function that does the real work. Returns C if not known. Don't worry if your platform does not provide a mechanism for this. Most do not need it and hence do not provide it, they just return an empty list. Returns a reference to the installed function.