Specifications

187
Syntax:
COMMON commonvariable[,commonvariable...]
Parameter:
commonvariable
A non-array integer variable, a non-array real variable, a non-array string
variable, an array integer variable, an array real variable, or an array string
variable.
Description:
COMMON defines common variables for sharing them when one program chains to
another.
• Common variables defined by
COMMON keep effective as long as programs
chained by the CHAIN statement are running.
• A
COMMON statement can appear anywhere in a source program.
• All of the variable name, type, quantity, and definition order of common variables
used in the current program should be identical with those in the chained-to pro-
grams. If not, variables having indefinite values will be passed.
• Up to two-dimensional array variables can be defined. You can specify a sub-
script ranging from 0 to 254 for an array variable.
• The total variable data size which can be passed between chained programs is 6
kilobytes including work variables.
• The size of an array data is equal to the element size multiplied by the number of
elements.
• You can specify the maximum string length within the range from 1 to 255 to a
string variable.
• The default length of a non-array string variable is 40.
• The default length of an array string variable is 20.
Declarative statement
COMMON
Declares common variables for sharing between user programs.