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GlobalDataDef
Semantics
The player type GlobalDataDef corresponds to an exported data definition that is named and typed. Global data definitions are defined at the outer-most scope in a compilation unit and are made globally available for reference from anywhere within the process boundary in which it is defined.
A GlobalDataDef player does not correspond to a shared memory location in the operating system environment that can be accessed by code in different processes. It does represent data that can be accessed by any code within a process.
Component Types In
A player of type GlobalDataDef can legally be defined in components of the following types:
It cannot be defined in a component of type Computation because it breaks the abstraction of a purely computational unit that does not maintain state.
Role Type
Associations
A player of type GlobalDataDef can legally be associated with the following role types in connections of the specified type:
Properties
The following properties can be legally included in the property list of a GlobalDataDef player:
- The syntax for the MaxAssocs property in a GlobalDataDef player is a single <integer> surrounded by parentheses:
- MAXASSOCS (1)
- The syntax for the MinAssocs property in a GlobalDataDef player is a single <integer> surrounded by parentheses:
- MINASSOCS (0)
- The syntax for the Signature property in a GlobalDataDef player is a single <identifier> or "string" surrounded by parentheses:
- SIGNATURE (int)
SIGNATURE ("char *")
Implementation Considerations
An example of a GlobalDataDef player in the implementation would be an external variable definition in a C source code file. The following are examples:
/* defined anywhere in a C source code such a definition is legal */
extern int my_global_variable;
/* defined at the outer-most scope of a C source code file */
int another_global_variable;
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Author:
Gregory Zelesnik
Last Modified: May 12, 1996