LIKE vs. LIKEDS

Please excuse me but I seem to be experiencing brain fade at the moment...

What's the difference between using LIKE vs. LIKEDS 

In particular, say you've got a ds like so...

     d t_SysObjName    s             10a   based( TEMPLATE )

     d t_QualifiedObj  ds                  qualified based( TEMPLATE )
     d  objectName                         like( t_SysObjName )
     d  libraryName                        like( t_SysObjName )

Now, say you are working with an IBM API, for example Create User Space
     d QusCrtUsrSpace  PR                  ExtPgm('QUSCRTUS')
     d  userSpaceName                      Const like( t_QualifiedObj )

Does it matter if I use LIKE or LIKEDS here?  The API is of course actually 
expecting a 20 character field.

Now, let's say I want to pass the structure to my own procedure.  In that 
procedure I want to access the subfields without copying the data to some other 
structure, or using a based structure.  In this case, I always want LIKEDS 
correct?


Thanks,

Charles Wilt
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121