Service Programs 101

This should be a quick one for most of you.  What exactly is a service
program, or rather, how are they implemented?  Is a service program like a
compiled, standalone subroutine or module of multiple subroutines?  I've
read the comments people have made in reference to them but haven't had a
need for them so far.  I'm still getting my feet wet with procedures and
procedure interfaces.  (I've used them for CALLP's and for replacing *ENTRY
PLIST).  This may or may not be applicable but I am familiar with creating
RPG modules and then binding them into a executable program.

Specifically, I've been adapting some of Scott Klement's code for reading
and writing to the IFS in preparation for a project that's coming up.  It's
been going good so far but one of the examples creates a service program
and uses it in later programs.  I want to try to use it in my program but
I'm not sure if I understand the implementation.
The service program was successfully created in QGPL.
I'm using a /COPY member of Scott's to define the procedure.
I get the following error when I try to do a CRTBNDRPG on my program.  Do I
need to create my program as a module and then bind it to the service
program?


MY ERROR MESSAGE:
Message . . . . :   Definition not found for symbol 'READLINE'.
Cause . . . . . :   No definition was found for reference READLINE in
*MODULE
  object NISCOTST1 in library QTEMP. The definition either does not exist
or
  is not of the same data or procedure type as the reference. Recovery  . .
.
  :   Try the Create Program (CRTPGM) command again, supplying an object
that
  contains a definition for symbol READLINE.


The service program was created in QGPL which is in my library list.
SERVICE PROGRAM CODE SNIPPET:
P readline        B                   export
D readline        PI            10I 0
D   fd                          10I 0 value
D   text                          *   value
D   maxlen                      10I 0 value


/COPY SNIPPET:
D readline        PR            10I 0
D   fd                          10I 0 value
D   text                          *   value
D   maxlen                      10I 0 value

MY CODE SNIPPET:
C                   dow       readline(fd: %addr(line): %size(line))>=0


Any help or advice would be appreciated.


Dave Parnin
Nishikawa Standard Company
Topeka, IN  46571
daparnin@xxxxxxxxxxxxxxxxxx