LibraryInterceptor is an example of using the SetFunction() in the 
exec.library to patch system library calls.  The source is included
& has been compiled with SAS-C V6.58.  You should run it from a 
CLI/Shell & then run the program whose library openings you wish to 
examine/change.  The GUI allows you to change the name or version
of the library being opened.

WARNING! WARNING! Danger, Will Robinson!

You should really know what you're doing to use this feature of the 
program.  Incorrect usage will freeze your Amiga or result in loss 
of data!

Use the Restore Parm's button to return to the original arguments 
that were called for, then press the Open Library button.  The Kill 
Interceptor button will cause the patch to be removed & the
program will terminate (if nothing else has patched the OpenLibrary() 
vector).

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                22252   45076  49.4% -lh5- 8c14 Feb 21  2001 LIProgram/InterceptTest
[generic]                  489    1220  40.1% -lh5- 6f27 Feb 21  2001 LIProgram/InterceptTest.c
[generic]                15143   25408  59.6% -lh5- 2376 Feb 21  2001 LIProgram/LibraryInterceptor
[generic]                 4651   16654  27.9% -lh5- 6f29 Feb 21  2001 LIProgram/LibraryInterceptor.c
[generic]                  587    1039  56.5% -lh5- 5a3b Feb 21  2001 LIProgram/LibraryInterceptor.readme
[generic]                  450    1189  37.8% -lh5- 89e6 Feb 21  2001 LIProgram/SMakeFile
[generic]                  587    1039  56.5% -lh5- 5a3b Feb 21  2001 LibraryInterceptor.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         7 files   44159   91625  48.2%            Feb 22  2001