Vector Basic Interpreter Basic 80 Reference Manual - page 31
of
190
The Microsoft BASIC compiler
does
not
support
the ALL, MERGE, and DELETE options to CRAIN.
If
you wish
to
maintain
compatibility
with
the
BASIC compiler, it is recommended that COMMON be
used to pass variables and that overlays not
be
used.
If the MERGE option
is omitted,
CHAIN does not
preserve
variable
types
or
user-defined
functions for use by the chained proqram.
That
is, any OEFINT, OEFSNG, OEFDBL, DEFSTR, or DEFFN
statement containing shared variables
must
be
restated in the chained program.