UniBasic Commands Reference - Rocket Software

Variables in a common area must be declared the same type, dimension, and
in the same order by all programs accessing them. Programs can declare
more or fewer variables, and can change the name of the variables. The
order of the names in a program’s COMMON statement determines which
names go with which values.
Common names are limited to a length of seven characters. No error
message is returned when longer names are truncated during compilation.
In the following example, STRING2 overwrites STRING1 because both
names, commons1 and commons2, are truncated to “commons”:
COMMON commons1 STRING1
COMMON commons2 STRING2
COMMON BASICTYPEs
You can pass variables using common in any BASICTYPE. Here are some notes:
With BASICTYPEs M and P, use of COMMON is more flexible because in
these BASICTYPEs no zero element is maintained in arrays. For example,
two programs declare COMMON, which are described in the following
table.
STACKCOMMON defaults to OFF in BASICTYPEs R and U, but is
always ON in BASICTYPEs P and M.
You can use the PASSCOM option for compatibility purposes, but its use is
not needed to pass common variables.
STACKCOMMON
First Program Second Program
Declares COMMON as:
A,B(5)
Assigns values of:
A = 4 and B(3) = 5
Declares COMMON as:
U,V,W,X,Y,Z
Therefore:
U = 4 and X = 5
Example Renaming COMMON Variables
The ECL STACKCOMMON command makes use of common areas more flexible,
although it requires additional memory. STACKCOMMON settings have the
following effects:
COMMON 1-160