ACC: Global Variable Limitations - Exceeds 64K Segment

• Microsoft Access versions 2.0, 7.0, 97

SYMPTOMS

Moderate: Requires basic macro, coding, and interoperability skills.

Depending on how variables are declared in Microsoft Access 2.0, they can either end up in the Stack (approximately 64 kilobyte (K) limit) or on the Heap. When declaring variables as either Global or fixed-length strings, the error message "Out of Memory" will occur if a 64K memory segment limit is encountered. This is a cumulative total. In other words, the size of variable X plus the size of variable Y cannot exceed the approximate 64K limit.

When declaring variables in Microsoft Access 7.0 and 97, they contain an approximate 64K limit per fixed-length string, regardless of how the variables are dimensioned (local or global). The error message "Invalid length for fixed-length string" will occur if a fixed-length string exceeds the approximate 64K limit. This is not a cumulative total. In other words, variable X and variable Y can each be approximately 64K in size. The actual size allowed per fixed-length string in Microsoft Access 7.0 and 97 is 65,526 bytes.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a module and type the followings line in the Declarations section:

         Option Explicit
         Global x as String * 66000
   

         ' NOTE: In Microsoft Access 2.0, the amount of the declarations are
         ' cumulative. The error can be caused by these three Global
         ' statements which exceed the limit when added together.
   

         Option Explicit
         Global x as String * 30000
         Global y as String * 30000
         Global z as String * 30000
   

STATUS

This behavior is by design.