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12. Generic Units
12. Generic Units
- 1
- A generic unit is a program unit that is either a generic subprogram or a generic package. A generic unit is a template, which is parameterized or not, and from which corresponding (nongeneric) subprograms or packages can be obtained. The resulting program units are said to be instances of the original generic unit.
- 2
- A generic unit is declared by a generic declaration. This form of declaration has a generic formal part declaring any generic formal parameters. An instance of a generic unit is obtained as the result of a generic instantiation with appropriate generic actual parameters for the generic formal parameters. An instance of a generic subprogram is a subprogram. An instance of a generic package is a package.
- 3
- Generic units are templates. As templates they do not have the properties that are specific to their nongeneric counterparts. For example, a generic subprogram can be instantiated but it cannot be called. In contrast, the instance of a generic subprogram is a nongeneric subprogram; hence, this instance can be called but it cannot be used to produce further instances.
- 4
- References:

- declaration 3.1

- generic actual parameter 12.3

- generic declaration 12.1

- generic formal parameter 12.1

- generic formal part 12.1

- generic instantiation 12.3

- generic package 12.1

- generic subprogram 12.1

- instance 12.3

- package 7

- program unit 6

- subprogram 6
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