| Optimization / Runtime system basics | |
By definition, global variables are visible to all modules of a program, and thus shared among all modules of the program. While global variables are an easy way to share data among multiple modules, it is not recommended that you use too many global variables.
The data type definitions are only defined once in memory and shared by all modules of a program instance. By data type definition we mean the type descriptions, not the data itself. This applies only to the equivalent data types used in different modules.