Ada 2012 Reference Manual

J.15.11 Pragmas Priority and Interrupt_Priority

Syntax

The form of a pragma Priority is as follows:

pragma Priority (expression);

The form of a pragma Interrupt_Priority is as follows:

pragma Interrupt_Priority [(expression);]

Name Resolution Rules

The expected type for the expression in a Priority or Interrupt_Priority pragma is Integer.

Legality Rules

A Priority pragma is allowed only immediately within a task_definition, a protected_definition, or the declarative_part of a subprogram_body. An Interrupt_Priority pragma is allowed only immediately within a task_definition or a protected_definition.

For a Priority pragma that appears in the declarative_part of a subprogram_body, the expression shall be static, and its value shall be in the range of System.Priority.

Static Semantics

For an implementation that supports Annex D, a pragma Priority specifies the value of the Priority aspect (see D.1) and a pragma Interrupt_Priority specifies the value of the Interrupt_Priority aspect as follows:

If the pragma appears in a task_definition, the expression is associated with the aspect for the task type or single_task_declaration that contains the pragma;

If the pragma appears in a protected_definition, the expression is associated with the aspect for the protected type or single_protected_declaration that contains the pragma;

If the pragma appears in the declarative_part of a subprogram_body, the expression is associated with the aspect for the subprogram that contains the pragma.

If there is no expression in an Interrupt_Priority pragma, the Interrupt_Priority aspect has the value Interrupt_Priority'Last.