This attribute is required for dynamic invocation of a DLL or shared library. The AVM verifies the validity and existence of the LIBRARY value at run time when the call object's INVOKE( ) method is called.
If LIBRARY specifies a full path name, the AVM searches only that path for the shared library. Otherwise, the AVM first determines if the shared library is loaded in memory. If it is not loaded in memory, the AVM looks for the shared library in the current working directory. If the shared library cannot be found at this point:
On Windows the AVM uses the standard Windows search algorithm to find the DLL, the same algorithm used to find Windows executable (.exe) files
On UNIX the AVM continues searching for the shared library using the ABL PROPATH