ATPLoad
ATPLoad Load .ATP driver
#include <AppleTalk.h> AppleTalk Manager
returns Error Code; 0=no error
ATPLoad first checks whether the .MPP driver is already loaded and
running. If it is not, ATPLoad verifies that port B is configured for AppleTalk
and is not in use, and loads MPP into the system heap. ATPLoad then loads the
.ATP driver, unless it's already in memory. On a Macintosh 128K, ATPLoad
reads the .ATP driver from the system resource file into the application heap;
on any Macintosh later than the 128K, ATP is read into the system heap.
Returns: an OSErr; an integer Error Code. It will be one of:
noErr (0) No error
portInUse (-97) Port B is already in use
portNotCf (-98) Port B not configured for AppleTalk

Notes: On any Macintosh later than the 128K, ATPLoad and MPPOpen perform
essentially the same function.