A similar function can also be found on the FB^3 CD-ROM.

Sylvain



> It was discussed earlier that there are a few shortcoming in the runtime
> function FBTestForLibrary.
> 
> It only tests for the presence of the library.  Testing for the library won't
> prevent crashing if a function isn't included in the version of library that
> you test.
> 
> In many cases Apple has major major changes to the system and certain features
> might not be present on older machines.  In other cases finding the library
> itself might not be enough.  In those cases you need to test for the library
> and see if a certain function (or symbol) is present.
> 
> I recommend that in addition to FBTestForLibrary we have this function I have
> included below.  In this function you pass it the library name as before and
> the name of the function you want to test for.
> 
> For instance 'InterfaceLib' is always available on pre-MacOS X systems but
> some functions are not available on older systems.  FindFolder is available
> from Sys 7.1 and up but FindFolderExtended is only available from Mac OS 9.0
> and up.  If you want to use FindFolderExtended you could test Gestalt for the
> sys version but this also works where Gestalt fails.
> 
> The function is quite simple, it just tests for the library and then uses
> FindSymbol to test for the symbol name.  I just patterned it after the
> function FBTestForLibrary
> 
> watch for line breaks (although I don't hard wrap)
> 
> clear local
> local fn FBTestForSymbol(@LibName&, @SymName&)
> dim bool as boolean
> dim symClass as byte
> dim &
> dim symAddr as long
> dim @ connID as long
> dim @ MainAddr as long
> dim @ msg$
> 
> // test for shared library first
> bool = fn GetSharedLibrary( LibName&.Nil$,_"pwpc",_kReferenceCFrag, connID,
> mainAddr, msg$ ) = _noErr
> if ( bool == _false ) then exit fn// can't find library
> 
> // err means symbol not found
> bool = fn FindSymbol( connID, SymName&.Nil$, symAddr, symClass ) = _noErr
> 
> end fn = bool