p1076_chap_04

The default initial value of a variable of an access

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Unformatted text preview: ariable of an access type is defined to be the value null for that type. NOTES 1--The value of a variable that is not a shared variable may be is17 modified by a variable assignment statement (see 8.5); such assignments take effect immediately. 2--The variables declared within a given procedure persist until that procedure completes and returns to the caller. For procedures that contain wait statements, a variable may therefore persist therefore persists18 from one point in simulation time to another, and the value in the variable is thus maintained over time. For processes, which never complete, all variables persist from the beginning of simulation until the end of simulation. 3--The subelements of a composite, declared variable are not declared variables.4-- Since the language guarantees mutual exclusion of accesses to shared data, but not the order of access to such data by multiple processes in the same simulation cycle, the use of shared varaibles can be both non-portable and non-deterministic. For example, consider the follow...
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