The numbers that are contained in indicator variables specify, to the application, varying values.
| Number Contained in Indicator Variable | Specification to the Application |
|---|---|
| A negative number (most commonly -1) | The associated input main variable is null, or a null value was successfully returned. |
| Zero | The associated input main variable is non-null or a non-null value was successfully returned with no exception conditions applied. |
| A positive number | Truncation has occurred when returning a character or byte string to the associated main variable. This value represents the original length of the string before truncation. |
An indicator variable is defined as a 2 byte integer (smallint). In C, this is declared as:
short identifier;
A host variable is recognized for use as an indicator only if the short characteristic is coded; int is not equivalent on any platform.