Version 1.14 of ai12s/amd2xcon.txt

Unformatted version of ai12s/amd2xcon.txt version 1.14
Other versions for file ai12s/amd2xcon.txt

!comment This file contains Corrigendum conflicts for Amendment 3 (Ada 202x).
!comment Conflicts occur when multiple issues change the same
!comment paragraph of the standard.
!comment This file (and the reading of it in the program) would need to
!comment be changed for a new Corrigendum or Amendment.
!comment The paragraphs must be in sorted order!!
!corrigendum 1.1.3(17/3)
!AI-0179-1
!AI-0265-1
@dinsa An implementation conforming to this International Standard may provide additional aspects, attributes, library units, and pragmas. However, it shall not provide any aspect, attribute, library unit, or pragma having the same name as an aspect, attribute, library unit, or pragma (respectively) specified in a Specialized Needs Annex unless the provided construct is either as specified in the Specialized Needs Annex or is more limited in capability than that required by the Annex. A program that attempts to use an unsupported capability of an Annex shall either be identified by the implementation before run time or shall raise an exception at run time. @dinst For an implementation that conforms to this Standard, the implementation of a language-defined unit shall abide by all postconditions, type invariants, and default initial conditions specified for the unit by this International Standard (see 11.4.2).
!corrigendum 1.2(3/2)
!AI-0058-1
!AI-0224-1
@drepl ISO/IEC 1539-1:2004, @i<Information technology @emdash Programming languages @emdash Fortran @emdash Part 1: Base language>. @dby ISO/IEC 1539-1:2018, @i<Information technology @emdash Programming languages @emdash Fortran @emdash Part 1: Base language>.
!corrigendum 2.1(4.1/3)
!AI-0004-1
!AI-0263-1
@drepl The semantics of an Ada program whose text is not in Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2011) is implementation defined. @dby The semantics of an Ada program whose text is not in Normalization Form C (as defined by Clause 21 of ISO/IEC 10646:2017) is implementation defined.
!corrigendum 2.3(4/3)
!AI-0004-1
!AI-0263-1
@dinsa An @fa<identifier> shall not contain two consecutive characters in category @fa<punctuation_connector>, or end with a character in that category. @dinst @s8<@i<Legality Rules>>
An identifier shall only contain characters that may be present in Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017).
!corrigendum 3.3(23.7/3)
!AI-0226-1
!AI-0228-1
@dinsa @xbullet<it is part of the object denoted by a @fa<function_call> or @fa<aggregate>; or> @dinst @xbullet<it is a value conversion or @fa<qualified_expression> where the operand denotes a view of a composite object that is known to be constrained; or>
!corrigendum 4.2.1(0)
!AI-0249-1
!AI-0295-1
@dinsc
Using one or more of the aspects defined below, a type may be specified to allow the use of one or more kinds of literals as values of the type.
@s8<@i<Static Semantics>>
The following nonoverridable, type-related operational aspects may be specified for any type @i<T>:
@xhang<@xterm<Integer_Literal> This aspect is specified by a @i<function_>@fa<name> that denotes a primitive function of @i<T> with one parameter of type String and a result type of @i<T>.>
@xhang<@xterm<Real_Literal> This aspect is specified by a @i<function_>@fa<name> that denotes a primitive function of @i<T> with one parameter of type String and a result type of @i<T>.>
@xhang<@xterm<String_Literal> This aspect is specified by a @i<function_>@fa<name> that denotes a primitive function of @i<T> with one parameter of type Wide_Wide_String and a result type of @i<T>.>
@xindent<A type with a specified String_Literal aspect is considered a @i<string type>.>
@s8<@i<Legality Rules>>
The Integer_Literal or Real_Literal aspect shall not be specified for a type @i<T> if the full view of @i<T> is a numeric type. The String_Literal aspect shall not be specified for a type @i<T> if the full view of @i<T> is a string type (in the absence of the String_Literal aspect specification). In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit.
@s8<@i<Dynamic Semantics>>
For the evaluation of an integer (or real) literal with expected type having an Integer_Literal (or Real_Literal) aspect specified, the value is the result of a call on the function specified by the aspect, with the parameter being a string with lower bound one whose value corresponds to the textual representation of the integer (or real) literal.
For the evaluation of a @fa<string_literal> with expected type having a String_Literal aspect specified, the value is the result of a call on the function specified by the aspect, with the parameter being the Wide_Wide_String with lower bound one that corresponds to the literal.
@s8<@i<Bounded (Run-Time) Errors>>
It is a bounded error if the evaluation of a literal with expected type having a corresponding _Literal aspect specified, propagates an exception. The possible effect is that an error is reported prior to run time, or Program_Error or the exception propagated by the evaluation is raised at the point of use of the value of the literal.
!corrigendum 4.3.1(17/3)
!AI-0086-1
!AI-0127-1
@drepl The value of a discriminant that governs a @fa<variant_part> @i<P> shall be given by a static expression, unless @i<P> is nested within a @fa<variant> @i<V> that is not selected by the discriminant value governing the @fa<variant_part> enclosing @i<V>. @dby For a @fa<record_aggregate> or @fa<extension_aggregate>, if a @fa<variant_part> @i<P> is nested within a @fa<variant> @i<V> that is not selected by the discriminant value governing the @fa<variant_part> enclosing @i<V>, then there is no restriction on the discriminant governing @i<P>. Otherwise, the value of the discriminant that governs @i<P> shall be given by a static expression, or by a nonstatic expression having a constrained static nominal subtype. In this latter case of a nonstatic expression, there shall be exactly one @fa<discrete_choice_list> of @i<P> that covers each value that belongs to the nominal subtype and satisfies the predicates of the subtype, and there shall be at least one such value.
!corrigendum 4.3.3(17/3)
!AI-0061-1
!AI-0127-1
@drepl The @fa<discrete_choice_list> of an @fa<array_component_association> is allowed to have a @fa<discrete_choice> that is a nonstatic @fa<choice_expression> or that is a @fa<subtype_indication> or @fa<range> that defines a nonstatic or null range, only if it is the single @fa<discrete_choice> of its @fa<discrete_choice_list>, and there is only one @fa<array_component_association> in the @fa<array_aggregate>. @dby The @fa<discrete_choice_list> of an @fa<array_component_association> (including an @fa<iterated_component_association>) is allowed to have a @fa<discrete_choice> that is a nonstatic @fa<choice_expression> or that is a @fa<subtype_indication> or @fa<range> that defines a nonstatic or null range, only if it is the single @fa<discrete_choice> of its @fa<discrete_choice_list>, and either there is only one @fa<array_component_association> in the enclosing @fa<array_component_association_list> or the enclosing @fa<aggregate> is an @fa<array_delta_aggregate>, not an @fa<array_aggregate>.
!corrigendum 5.5(3/3)
!AI-0119-1
!AI-0189-1
!AI-0251-1
@drepl @xcode<@fa<iteration_scheme>@fa< ::= >@ft<@b<while>> @fa<condition>
| @ft<@b<for>> @fa<loop_parameter_specification> | @ft<@b<for>> @fa<iterator_specification>>
@dby @xcode<@fa<iteration_scheme>@fa< ::= >@ft<@b<while>> @fa<condition>
| @ft<@b<for>> @fa<loop_parameter_specification> | @ft<@b<for>> @fa<iterator_specification> | @ft<@b<for>> @fa<procedural_iterator> | @ft<@b<parallel>> [(@fa<chunk_specification>)]
@ft<@b<for>> @fa<loop_parameter_specification>>
@xcode<@fa<chunk_specification>@fa< ::= >@ft<@i<integer_>>@fa<simple_expression>
| @fa<defining_identifier> @ft<@b<in>> @fa<discrete_subtype_definition>>
!corrigendum 5.5(5)
!AI-0119-1
!AI-0251-1
@dinsa If a @fa<loop_statement> has a @i<loop_>@fa<statement_identifier>, then the @fa<identifier> shall be repeated after the @b<end loop>; otherwise, there shall not be an @fa<identifier> after the @fa<end loop>.
@dinst An @fa<iteration_scheme> that begins with the reserved word @b<parallel> shall not have the reserved word @b<reverse> in its @fa<loop_parameter_specification>.
@s8<@i<Name Resolution Rules>>
In a @fa<chunk_specification> that is an @i<integer_>@fa<simple_expression>, the @i<integer_>@fa<simple_expression> is expected to be of any integer type.
!corrigendum 5.5(6)
!AI-0061-1
!AI-0251-1
@drepl A @fa<loop_parameter_specification> declares a @i<loop parameter>, which is an object whose subtype is that defined by the @fa<discrete_subtype_definition>. @dby A @fa<loop_parameter_specification> declares a @i<loop parameter>, which is an object whose subtype (and nominal subtype) is that defined by the @fa<discrete_subtype_definition>.
In a @fa<chunk_specification> that has a @fa<discrete_subtype_definition>, the @fa<chunk_specification> declares a @i<chunk parameter> object whose subtype (and nominal subtype) is that defined by the @fa<discrete_subtype_definition>.
!corrigendum 5.5(9/4)
!AI-0119-1
!AI-0251-1
!AI-0294-1
@drepl For the execution of a @fa<loop_statement> with the @fa<iteration_scheme> being @b<for> @fa<loop_parameter_specification>, the @fa<loop_parameter_specification> is first elaborated. This elaboration creates the loop parameter and elaborates the @fa<discrete_subtype_definition>. If the @fa<discrete_subtype_definition> defines a subtype with a null range, the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is executed once for each value of the discrete subtype defined by the @fa<discrete_subtype_definition> that satisfies the predicates of the subtype (or until the loop is left as a consequence of a transfer of control). Prior to each such iteration, the corresponding value of the discrete subtype is assigned to the loop parameter. These values are assigned in increasing order unless the reserved word @b<reverse> is present, in which case the values are assigned in decreasing order. @dby For the execution of a @fa<loop_statement> that has an @fa<iteration_scheme> including a @fa<loop_parameter_specification>, after elaborating the @fa<chunk_specification>, if any, the @fa<loop_parameter_specification> is elaborated. This elaboration elaborates the @fa<discrete_subtype_definition>, which defines the subtype of the loop parameter. If the @fa<discrete_subtype_definition> defines a subtype with a null range, the execution of the @fa<loop_statement> is complete. Otherwise, the @fa<sequence_of_statements> is executed once for each value of the discrete subtype defined by the @fa<discrete_subtype_definition> that satisfies the predicates of the subtype (or until the loop is left as a consequence of a transfer of control). Prior to each such iteration, the corresponding value of the discrete subtype is assigned to the loop parameter associated with the given iteration. If the loop is a parallel loop, each chunk has its own logical thread of control with its own copy of the loop parameter; otherwise (a @i<sequential loop>), a single logical thread of control performs the loop, and there is a single copy of the loop parameter. Each logical thread of control handles a distinct subrange of the values of the subtype of the loop parameter such that all values are covered with no overlaps. Within each logical thread of control, the values are assigned to the loop parameter in increasing order unless the reserved word @b<reverse> is present, in which case the values are assigned in decreasing order.
If a @fa<chunk_specification> with a @fa<discrete_subtype_definition> is present, then the logical thread of control associated with a given chunk has its own copy of the chunk parameter initialized with a distinct value from the discrete subtype defined by the @fa<discrete_subtype_definition>. The values of the chunk parameters are assigned such that they increase with increasing values of the ranges covered by the corresponding loop parameters.
Whether or not a @fa<chunk_specification> is present in a parallel loop, the total number of iterations of the loop represents an upper bound on the number of logical threads of control devoted to the loop.
!corrigendum 5.5.2(5/4)
!AI-0156-1
!AI-0183-1
@drepl The subtype defined by the @fa<subtype_indication>, if any, of an array component iterator shall statically match the component subtype of the type of the @i<iterable_>@fa<name>. The subtype defined by the @fa<subtype_indication>, if any, of a container element iterator shall statically match the default element subtype for the type of the @i<iterable_>@fa<name>. @dby The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of a generalized iterator shall statically match the iteration cursor subtype. The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of an array component iterator shall statically match the component subtype of the type of the @i<iterable_>@fa<name>. The subtype defined by the @fa<loop_parameter_subtype_indication>, if any, of a container element iterator shall statically match the default element subtype for the type of the @i<iterable_>@fa<name>.
!corrigendum 5.5.3(0)
!AI-0189-1
!AI-0292-1
!AI-0294-1
@dinsc
A @fa<procedural_iterator> invokes a user-defined procedure, passing in the body of the enclosing @fa<loop_statement> as a parameter of an anonymous access-to-procedure type, to allow the loop body to be executed repeatedly as part of the invocation of the user-defined procedure.
@s8<@i<Syntax>>
@xcode<@fa<procedural_iterator>@fa< ::= >
@fa<iterator_parameter_specification> @ft<@b<of>> @fa<iterator_procedure_call>>
@xcode<@fa<iterator_parameter_specification>@fa< ::= >
@fa<formal_part> | (@fa<identifier>{, @fa<identifier>})>
@xcode<@fa<iterator_procedure_call>@fa< ::= >
@ft<@i<procedure_>>@fa<name> | @ft<@i<procedure_>>@fa<prefix> @fa<iterator_actual_parameter_part>>
@xcode<@fa<iterator_actual_parameter_part>@fa< ::= >
(@fa<iterator_parameter_association> {, @fa<iterator_parameter_association>})>
@xcode<@fa<iterator_parameter_association>@fa< ::= >
@fa<parameter_association> | @fa<parameter_association_with_box>>
@xcode<@fa<parameter_association_with_box>@fa< ::= >
[ @ft<@i<formal_parameter_>>@fa<selector_name> =@> ] <@>>
At most one @fa<iterator_parameter_association> within an @fa<iterator_actual_parameter_part> shall be a @fa<parameter_association_with_box>.
@s8<@i<Name Resolution Rules>>
The @fa<name> or @fa<prefix> given in an @fa<iterator_procedure_call> shall resolve to denote a callable entity @i<C> that is a procedure, or an entry renamed as (viewed as) a procedure. When there is an @fa<iterator_actual_parameter_part>, the @fa<prefix> can be an @fa<implicit_dereference> of an access-to-subprogram value.
An @fa<iterator_procedure_call> without a @fa<parameter_association_with_box> is equivalent to one with an @fa<iterator_actual_parameter_part> with an additional @fa<parameter_association_with_box> at the end, with the @i<formal_parameter_>@fa<selector_name> identifying the last formal parameter of the callable entity denoted by the @fa<name> or @fa<prefix>.
An @fa<iterator_procedure_call> shall contain at most one @fa<iterator_parameter_association> for each formal parameter of the callable entity @i<C>. Each formal parameter without an @fa<iterator_parameter_association> shall have a @fa<default_expression> (in the profile of the view of @i<C> denoted by the @fa<name> or @fa<prefix>). This rule is an overloading rule (see 8.6).
The formal parameter of the callable entity @i<C> associated with the @fa<parameter_association_with_box> shall be of an anonymous access-to-procedure type @i<A>.
@s8<@i<Legality Rules>>
The anonymous access-to-procedure type @i<A> shall have at least one formal parameter in its parameter profile. If the @fa<iterator_parameter_specification> is a @fa<formal_part>, then this @fa<formal_part> shall be mode conformant with that of @i<A>. If the @fa<iterator_parameter_specification> is a list of @fa<identifier>s, the number of formal parameters of @i<A> shall be the same as the length of this list.
If the @fa<name> or @fa<prefix> given in an @fa<iterator_procedure_call> denotes an abstract subprogram, the subprogram shall be a dispatching subprogram.
@s8<@i<Static Semantics>>
A @fa<loop_statement> with an @fa<iteration_scheme> that has a @fa<procedural_iterator> is equivalent to a local declaration of a procedure P followed by a @fa<procedure_call_statement> that is formed from the @fa<iterator_procedure_call> by replacing the <@> of the @fa<parameter_association_with_box> with P'Access. The @fa<formal_part> of the locally declared procedure P is formed from the @fa<formal_part> of the anonymous access-to-procedure type @i<A>, by replacing the @fa<identifier> of each formal parameter of this @fa<formal_part> with the @fa<identifier> of the corresponding formal parameter or element of the list of @fa<identifier>s given in the @fa<iterator_parameter_specification>.
The following aspect may be specified for a subprogram or entry S that has at least one formal parameter of an anonymous access-to-subprogram type:
@xhang<@xterm<Allows_Exit> The Allows_Exit aspect is of type Boolean. The specified value shall be static. The Allows_Exit of an inherited primitive subprogram is True if Allows_Exit is True either for the corresponding subprogram of the progenitor type or for any other inherited subprogram that it overrides. If not specified or inherited as True, the Allows_Exit aspect of a subprogram or entry is False.>
@xindent<Specifying the Allows_Exit aspect True for a subprogram asserts that the subprogram is prepared to be completed by arbitrary transfers of control from the subprogram represented by the access-to-subprogram value, including propagation of exceptions. A subprogram for which Allows_Exit is True should use finalization for any necessary cleanup, and in particular should not use exception handling to implement cleanup.>
@s8<@i<Legality Rules>>
If a subprogram or entry overrides an inherited dispatching subprogram that has a True Allows_Exit aspect, only a confirming specification of True is permitted for the aspect on the overriding declaration.
The @fa<sequence_of_statements> of a @fa<loop_statement> with a @fa<procedural_iterator> as its @fa<iteration_scheme> shall contain an @fa<exit_statement>, return statement, @fa<goto_statement>, or @fa<requeue_statement> that leaves the loop only if the callable entity @i<C> associated with the @fa<procedural_iterator> has an Allows_Exit aspect specified True.
The @fa<sequence_of_statements> of a @fa<loop_statement> with a @fa<procedural_iterator> as its @fa<iteration_scheme> shall not contain an @fa<accept_statement>.
@s8<@i<Examples>>
Example of iterating over a map from My_Key_Type to My_Element_Type (see A.18.4):
@xcode<@b<for> (C : Cursor) @b<of> My_Map.Iterate @b<loop>
Put_Line (My_Key_Type'Image (Key (C)) & " =@> " &
My_Element_Type'Image (Element (C)));
@b<end loop>;>
@xcode<--@ft<@i< The above is equivalent to:>>>
@xcode<@b<declare>
@b<procedure> P (C : Cursor) @b<is> @b<begin>
Put_Line (My_Key_Type'Image (Key (c)) & " =@> " &
My_Element_Type'Image (Element (C)));
@b<end> P;
@b<begin>
My_Map.Iterator (P'access);
@b<end>;>
Example of iterating over the environment variables (see A.17):
@xcode<@b<for> (Name, Val) @b<of> Ada.Environment_Variables.Iterate(<@>) @b<loop>
--@ft<@i< "(<@>)" is optional because it is the last parameter>> Put_Line (Name & " =@> " & Val);
@b<end loop>;>
@xcode<--@ft<@i< The above is equivalent to:>>>
@xcode<@b<declare>
@b<procedure> P (Name : String; Val : String) @b<is> @b<begin>
Put_Line (Name & " =@> " & Val);
@b<end> P;
@b<begin>
Ada.Environment_Variables.Iterate (P'access);
@b<end>;>
!corrigendum 6.1.1(1/4)
!AI-0220-1
!AI-0272-1
@drepl For a noninstance subprogram, a generic subprogram, or an entry, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1): @dby For a noninstance subprogram (including a generic formal subprogram), a generic subprogram, an entry, or an access-to-subprogram type, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
!corrigendum 6.1.1(29/4)
!AI-0185-1
!AI-0220-1
@drepl @xhang<@xterm<F'Result>Within
a postcondition expression for function F, denotes the result object of the function. The type of this attribute is that of the function result except within a Post'Class postcondition expression for a function with a controlling result or with a controlling access result. For a controlling result, the type of the attribute is @i<T>'Class, where @i<T> is the function result type. For a controlling access result, the type of the attribute is an anonymous access type whose designated type is @i<T>'Class, where @i<T> is the designated type of the function result type.>
@dby @xhang<@xterm<F'Result>Within
a postcondition expression for F, denotes the return object of the function call for which the postcondition expression is evaluated. The type of this attribute is that of the result subtype of the function or access-to-function type except within a Post'Class postcondition expression for a function with a controlling result or with a controlling access result; in those cases the type of the attribute was described previously.>
!corrigendum 6.1.1(39/3)
!AI-0220-1
!AI-0272-1
@drepl For a call via an access-to-subprogram value, all precondition and postcondition checks performed are determined by the subprogram or entry denoted by the prefix of the Access attribute reference that produced the value. @dby For a call via an access-to-subprogram value, precondition and postcondition checks performed are as determined by the subprogram or entry denoted by the prefix of the Access attribute reference that produced the value. In addition, a precondition check of any precondition expression associated with the access-to-subprogram type is performed. Similarly, a postcondition check of any postcondition expression associated with the access-to-subprogram type is performed.
For a call on a generic formal subprogram, precondition and postcondition checks performed are as determined by the subprogram or entry denoted by the actual subprogram, along with any specific precondition and specific postcondition of the formal subprogram itself.
!corrigendum 7.3.2(8/3)
!AI-0075-1
!AI-0199-1
@drepl If the Type_Invariant'Class aspect is specified for a tagged type @i<T>, then the invariant expression applies to all descendants of @i<T>. @dby If the Type_Invariant'Class aspect is specified for a tagged type @i<T>, then a @i<corresponding expression> also applies to each nonabstract descendant @i<T1> of @i<T> (including @i<T> itself if it is nonabstract). The corresponding expression is constructed from the associated expression as follows:
@xbullet<References to non-discriminant components of @i<T> (or to @i<T> itself) are replaced with references to the corresponding components of @i<T1> (or to @i<T1> as a whole).>
@xbullet<References to discriminants of @i<T> are replaced with references to the corresponding discriminant of @i<T1>, or to the specified value for the discriminant, if the discriminant is specified by the @fa<derived_type_definition> for some type that is an ancestor of @i<T1> and a descendant of @i<T> (see 3.7).>
If one or more invariant expressions apply to a nonabstract type @i<T>, then a subprogram or entry is said to be @i<type-invariant preserving> for @i<T> if
@xbullet<it is declared within the immediate scope of @i<T> (or by an instance of a generic unit, and the generic is declared within the immediate scope of type @i<T>), or is the Read or Input stream-oriented attribute of type @i<T>, and either:>
@xinbull<@i<T> is a private type or a private extension and the subprogram or entry is visible outside the immediate scope of type @i<T> or overrides an inherited operation that is visible outside the immediate scope of @i<T>; or>
@xinbull<@i<T> is a record extension, and the subprogram or entry is a primitive operation visible outside the immediate scope of type @i<T> or overrides an inherited operation that is visible outside the immediate scope of @i<T>.>
@xbullet<and at least one of the following applies to the callable entity:>
@xinbull<has a result with a part of type @i<T>;> @xinbull<has one or more @b<out> or @b<in out> parameters with a part of type @i<T>;> @xinbull<has an access-to-object parameter or result whose designated type has a part of type @i<T>; or> @xinbull<is a procedure or entry that has an @b<in> parameter with a part of type @i<T>.>
@xindent<Each such part of type @i<T> is said to be @i<subject to an invariant check> for @i<T>.>
!corrigendum 7.3.2(20/3)
!AI-0075-1
!AI-0193-1
@ddel The check is performed on each such part of type @i<T>.
!corrigendum 7.3.3(0)
!AI-0265
!AI-0272
@dinsc
For a private type or private extension (including a generic formal type), the following language-defined aspect may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Default_Initial_Condition>This aspect shall be specified by an @fa<expression>, called a @i<default initial condition expression>. Default_Initial_Condition may be specified on a @fa<private_type_declaration>, a @fa<private_extension_declaration>, a @fa<formal_private_type_definition>, or a @fa<formal_derived_type_definition>.>
@s8<@i<Name Resolution Rules>>
The expected type for a default initial condition expression is any boolean type.
@s8<@i<Legality Rules>>
The Default_Initial_Condition aspect shall not be specified for a type whose partial view has unknown discriminants, whether explicitly declared or inherited.
@s8<@i<Static Semantics>>
If the Default_Initial_Condition aspect is specified for a type T, then the default initial condition expression applies to T and to all descendants of T.
@s8<@i<Dynamic Semantics>>
If one or more default initial condition expressions apply to a type T, then a default initial condition check is performed after successful default initialization of an object of type T by default (see 3.3.1). In the case of a controlled type, the check is performed after the call to the type's Initialize procedure (see 7.6).
If performing checks is required by the Default_Initial_Condition assertion policy (see 11.4.2) in effect at the point of the corresponding @fa<aspect_specification> applicable to a given type, then the respective default initial condition expression is considered enabled.
The default initial condition check consists of the evaluation of each enabled default initial condition expression that applies to T. These evaluations, if there are more than one, are performed in an arbitrary order. If any of these evaluate to False, Assertions.Assertion_Error is raised at the point of the object initialization.
For a generic formal type T, default initial condition checks performed are as determined by the actual type, along with any default initial condition of the formal type itself.
!corrigendum 7.3.4(0)
!AI-0187-1
!AI-0272-1
!AI-0285-1
@dinsc
It is usual that some of the characteristics of a data type are unchanged by most of the primitive operations on the type. Such characteristics are called @i<stable properties> of the type.
@s8<@i<Static Semantics>>
A @i<property function> of type @i<T> is a function with a single parameter of type @i<T> or of a class-wide type that covers @i<T>.
A @i<type property aspect definition> is a list of @fa<name>s written in the syntax of a @fa<positional_array_aggregate>. A @i<subprogram property aspect definition> is a list of @fa<name>s preceded by an optional @b<not> written in the syntax of a @fa<positional_array_aggregate>.
For a nonformal private type, nonformal private extension, or full type that does not have a partial view, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Stable_Properties>This aspect
shall be specified by a type property aspect definition; each @fa<name> shall statically denote a single property function of the type. This aspect defines the @i<stable property functions> of the associated type.>
@xhang<@xterm<Stable_Properties'Class>This aspect
shall be specified by a type property aspect definition; each @fa<name> shall statically denote a single property function of the type. This aspect defines the @i<class-wide stable property functions> of the associated type. Unlike most class-wide aspects, Stable_Properties'Class is not inherited by descendant types and subprograms, but the enhanced class-wide postconditions are inherited in the normal manner.>
For a primitive subprogram, the following language-defined aspects may be specified with an @fa<aspect_specification> (see 13.1.1):
@xhang<@xterm<Stable_Properties>This aspect
shall be specified by a subprogram property aspect definition; each @fa<name> shall statically denote a single property function of a type for which the associated subprogram is primitive.>
@xhang<@xterm<Stable_Properties'Class>This aspect
shall be specified by a subprogram property aspect definition; each @fa<name> shall statically denote a single property function of a tagged type for which the associated subprogram is primitive. Unlike most class-wide aspects, Stable_Properties'Class is not inherited by descendant subprograms, but the enhanced class-wide postconditions are inherited in the normal manner.>
@s8<@i<Legality Rules>>
A stable property function of a type @i<T> (including a class-wide stable property function) shall have a nonlimited return type and shall be:
@xbullet<a primitive function with a single parameter of mode @b<in> of type @i<T>; or>
@xbullet<a function that is declared immediately within the declarative region in which an ancestor type of @i<T> is declared and has a single parameter of mode @b<in> of a class-wide type that covers @i<T>.>
In a subprogram property aspect definition for a subprogram @i<S>:
@xbullet<all or none of the items shall be preceded by @b<not>;>
@xbullet<any property functions mentioned after @b<not> shall be a stable property function of a type for which @i<S> is primitive.>
@s8<@i<Static Semantics>>
For a primitive subprogram @i<S> of a type @i<T>, the stable property functions for @i<S> for type @i<T> are:
@xbullet<if @i<S> has an aspect Stable_Properties specified that does not include @b<not>, those functions denoted in the aspect Stable_Properties for @i<S> that have a parameter of @i<T> or @i<T>'Class;>
@xbullet<if @i<S> has an aspect Stable_Properties specified that includes @b<not>, those functions denoted in the aspect Stable_Properties for @i<T>, excluding those denoted in the aspect Stable_Properties for @i<S>;>
@xbullet<if @i<S> does not have an aspect Stable_Properties, those functions denoted in the aspect Stable_Properties for @i<T>, if any.>
A similar definition applies for class-wide stable property functions by replacing aspect Stable_Properties with aspect Stable_Properties'Class in the above definition.
The @i<explicit> specific postcondition expression for a subprogram @i<S> is the @fa<expression> directly specified for @i<S> with the Post aspect. Similarly, the @i<explicit> class-wide postcondition expression for a subprogram @i<S> is the @fa<expression> directly specified for @i<S> with the Post'Class aspect.
For every primitive subprogram @i<S> of a type @i<T> that is not a stable property function of @i<T>, the specific postcondition expression of @i<S> is modified to include expressions of the form @fc<@i<F>(@i<P>) = @i<F>(@i<P>)'Old>, all @b<and>ed with each other and any explicit specific postcondition expression, where @i<F> is each stable property function of @i<S> for type @i<T> that does not occur in the explicit specific postcondition expression of @i<S>, and @i<P> is each parameter of @i<S> that has type @i<T>. The resulting specific postcondition expression of @i<S> is used in place of the explicit specific postcondition expression of @i<S> when interpreting the meaning of the postcondition as defined in 6.1.1.
For every primitive subprogram @i<S> of a type @i<T> that is not a stable property function of @i<T>, the class-wide postcondition expression of @i<S> is modified to include expressions of the form @fc<@i<F>(@i<P>) = @i<F>(@i<P>)'Old>, all @b<and>ed with each other and any explicit class-wide postcondition expression, where @i<F> is each class-wide stable property function of @i<S> for type @i<T> that does not occur in any class-wide postcondition expression that applies to @i<S>, and @i<P> is each parameter of @i<S> that has type @i<T>. The resulting class-wide postcondition expression of @i<S> is used in place of the explicit class-wide postcondition expression of @i<S> when interpreting the meaning of the postcondition as defined in 6.1.1.
@xindent<@s9<NOTES@hr 14 For an example of the use of these aspects, see the Vector container definition in A.18.2.>>
!corrigendum 9.5(17/3)
!AI-0064-2
!AI-0247-1
!AI-0267-1
@dinsa In addition to the places where Legality Rules normally apply (see 12.3), these rules also apply in the private part of an instance of a generic unit. @dinss @s8<@i<Static Semantics>>
An @fa<expression> is @i<nonblocking-static> if it is one of the following:
@xbullet<a static expression;>
@xbullet<a Nonblocking @fa<attribute_reference>;>
@xbullet<a call to a predefined boolean logical operator @b<and> where each operand is nonblocking-static;>
@xbullet<an @b<and then> short-circuit control form where each operand is nonblocking-static;>
@xbullet<a parenthesized nonblocking-static @fa<expression>.>
For a program unit, task entry, formal package, formal subprogram, formal object of an anonymous access-to-subprogram type, enumeration literal, and for a type (including a formal type), the following language-defined operational aspect is defined:
@xhang<@xterm<Nonblocking> This aspect specifies the blocking restriction for the entity; it shall be specified by an @fa<expression>, called a @i<nonblocking expression>. If directly specified, the @fa<aspect_definition> shall be a nonblocking-static expression. The expected type for the @fa<expression> is the predefined type Boolean. The @fa<aspect_definition> can be omitted from the specification of this aspect; in that case the nonblocking expression for the entity is the enumeration literal True.>
@xindent<The Nonblocking aspect may be specified for all entities for which it is defined, except for protected operations and task entries. In particular, Nonblocking may be specified for generic formal parameters.>
@xindent<When the nonblocking expression is static for an entity, the expression is evaluated to produce a static value for the aspect. When aspect Nonblocking is statically False for an entity, the entity might contain a potentially blocking operation; such an entity @i<allows blocking>. If the aspect is statically True for an entity, the entity is said to be @i<nonblocking>.>
@xindent<For a generic instantiation and entities declared within such an instance, the aspect is determined by the nonblocking expression for the corresponding entity of the generic unit, with any Nonblocking attributes of the generic formal parameters replaced by the appropriate nonblocking expression of the corresponding actual parameters. If the aspect is directly specified for an instance, the specified expression shall be static and have the same value as the nonblocking expression of the instance (after replacement).>
@xindent<For a (protected or task) entry, the Nonblocking aspect is the Boolean literal False.>
@xindent<For an enumeration literal, the Nonblocking aspect is the Boolean literal True.>
@xindent<For a predefined operator of an elementary type, the Nonblocking aspect is the Boolean literal True. For a predefined operator of a composite type, the Nonblocking aspect of the operator is the same as the Nonblocking aspect for the type.>
@xindent<For a dereference of an access-to-subprogram type, the Nonblocking aspect of the designated subprogram is that of the access-to-subprogram type.>
@xindent<For a full type declaration that has a partial view, the aspect is the same as that of the partial view.>
@xindent<For an inherited primitive dispatching subprogram that is null or abstract, the subprogram is nonblocking if and only if a corresponding subprogram of at least one ancestor is nonblocking. For any other inherited subprogram, it is nonblocking if and only if the corresponding subprogram of the parent is nonblocking.>
@xindent<Unless directly specified, overridings of dispatching operations inherit this aspect.>
@xindent<Unless directly specified, for a formal type, formal package, or formal subprogram, the Nonblocking aspect is that of the actual type, package, or subprogram.>
@xindent<Unless directly specified, for a derived type, the Nonblocking aspect is that of the parent type.>
@xindent<Unless directly specified, for any other program unit, type, or formal object, the Nonblocking aspect of the entity is determined by the Nonblocking aspect for the innermost program unit enclosing the entity.>
@xindent<If not specified for a library unit, the nonblocking expression is the Boolean literal True if the library unit is declared pure and is not a generic unit, or the Boolean literal False otherwise.>
For a @fa<prefix> S that denotes a subprogram (including a formal subprogram):
@xhang<@xterm<S'Nonblocking> Denotes whether subprogram S is considered nonblocking; the type of this attribute is the predefined type Boolean.>
@xindent<The @fa<prefix> S shall statically denote a subprogram.>
@xindent<S'Nonblocking represents the nonblocking expression of S; evaluation of S'Nonblocking evaluates that expression.>
For a @fa<prefix> P that denotes a package (including a formal package):
@xhang<@xterm<P'Nonblocking> Denotes whether package P is considered nonblocking; the type of this attribute is the predefined type Boolean. P'Nonblocking represents the nonblocking expression of P; evaluation of P'Nonblocking evaluates that expression.>
For a @fa<prefix> S that denotes a subtype (including formal subtypes):
@xhang<@xterm<S'Nonblocking> Denotes whether predefined operators (and in the case of access-to-subprogram subtypes) a subprogram designated by a value of type S are considered nonblocking; the type of this attribute is the predefined type Boolean. S'Nonblocking represents the nonblocking expression of S; evaluation of S'Nonblocking evaluates that expression.>
The following are defined to be @i<potentially blocking> operations:
@xbullet<a @fa<select_statement>;>
@xbullet<an @fa<accept_statement>;>
@xbullet<an @fa<entry_call_statement>, or a call on a procedure that renames or is implemented by an entry;>
@xbullet<a @fa<delay_statement>;>
@xbullet<an @fa<abort_statement>;>
@xbullet<task creation or activation;>
@xbullet<during a protected action, an external call on a protected subprogram (or an external requeue) with the same target object as that of the protected action.>
If a language-defined subprogram allows blocking, then a call on the subprogram is a potentially blocking operation.
@s8<@i<Legality Rules>>
A parallel construct or a nonblocking program unit shall not contain, other than within nested units with Nonblocking specified as statically False, a call on a callable entity for which the Nonblocking aspect is statically False, nor shall it contain any of the following:
@xbullet<a @fa<select_statement>;>
@xbullet<an @fa<accept_statement>;>
@xbullet<a @fa<delay_statement>;>
@xbullet<an @fa<abort_statement>;>
@xbullet<task creation or activation.>
For the purposes of the above rule, an @fa<entry_body> is considered nonblocking if the immediately enclosing protected unit is nonblocking.
A subprogram shall be nonblocking if it overrides a nonblocking dispatching operation. An entry shall not implement a nonblocking procedure. If an inherited dispatching subprogram allows blocking, then the corresponding subprogram of each ancestor shall allow blocking.
It is illegal to specify aspect Nonblocking for the full view of a type that has a partial view.
Aspect Nonblocking shall be specified for a derived type only if it fully conforms to the nonblocking expression of the ancestor type or if it is specified to have the Boolean literal True.
If aspect Nonblocking is specified for an entity that is not a generic unit or declared inside of a generic unit, the @fa<aspect_definition> shall be a static expression.
If the prefix of a Nonblocking @fa<attribute_reference> denotes a generic unit @i<G>, the reference shall occur within the declarative region of @i<G>.
The predefined equality operator for a composite type is illegal if it is nonblocking and, for a record type, it is not overridden by a primitive equality operator, and:
@xbullet<for a record type, the parent primitive "=" allows blocking; or>
@xbullet<any component that has a record type that has a primitive "=" that allows blocking; or>
@xbullet<any component that has a non-record type that has a predefined "=" that allows blocking.>
In a generic instantiation (after replacement in the nonblocking expressions by values of the actuals as described previously):
@xbullet<the actual subprogram corresponding to a nonblocking formal subprogram shall be nonblocking (an actual that is an entry is not permitted in this case);>
@xbullet<the actual type corresponding to a nonblocking formal private, derived, array, or access-to-subprogram type shall be nonblocking;>
@xbullet<the actual object corresponding to a formal object of a nonblocking access-to-subprogram type shall be of a nonblocking access-to-subprogram type;>
@xbullet<the actual instance corresponding to a nonblocking formal package shall be nonblocking.>
In addition to the places where Legality Rules normally apply (see 12.3), the above rules also apply in the private part of an instance of a generic unit.
A program unit @i<P> declared inside of a generic unit but not in a generic body or that is a generic specification not declared in a generic unit is considered nonblocking for the purposes of checking the restrictions on a nonblocking unit only if the value of its Nonblocking aspect is statically True. For the purposes of checks in @i<P>, a call to a subprogram is considered nonblocking unless the value of its Nonblocking aspect is statically False.
A program unit @i<P> declared inside of a generic body or that is a generic body is considered nonblocking for the purposes of checking the restrictions on a nonblocking unit unless the value of its Nonblocking aspect is statically False. For the purposes of checks in @i<P>, a call to a subprogram is considered to allow blocking unless:
@xbullet<the value of its Nonblocking aspect is statically True, or>
@xbullet<its nonblocking expression (that is, Nonblocking aspect) conforms exactly to that of @i<P>, or conforms to some part of the nonblocking expression of @i<P> that is combined with the remainder of the nonblocking expression of @i<P> by one or more @b<and> or @b<and then> operations.>
!corrigendum 9.5.1(18)
!AI-0064-2
!AI-0247-1
@drepl Certain language-defined subprograms are potentially blocking. In particular, the subprograms of the language-defined input-output packages that manipulate files (implicitly or explicitly) are potentially blocking. Other potentially blocking subprograms are identified where they are defined. When not specified as potentially blocking, a language-defined subprogram is nonblocking. @dby During a protected action, a call on a subprogram whose body contains a potentially blocking operation is a bounded error. If the bounded error is detected, Program_Error is raised; otherwise, the call proceeds normally.
!corrigendum 11.4.2(23.1/3)
!AI-0179-1
!AI-0265-1
@dinsa It is a bounded error to invoke a potentially blocking operation (see 9.5.1) during the evaluation of an assertion expression associated with a call on, or return from, a protected operation. If the bounded error is detected, Program_Error is raised. If not detected, execution proceeds normally, but if it is invoked within a protected action, it might result in deadlock or a (nested) protected action. @dinss @s8<@i<Implementation Requirements>>
Any postcondition expression, type invariant expression, or default initial condition expression occurring in the specification of a language-defined unit is enabled (see 6.1.1, 7.3.2, and 7.3.3).
The evaluation of any such postcondition, type invariant, or default initial condition expression shall either yield True or propagate an exception from a @fa<raise_expression> that appears within the assertion expression.
!corrigendum 12.6(8.2/2)
!AI-0183-1
!AI-0287-1
@drepl @xbullet<if the actual matching the @fa<formal_subprogram_declaration> denotes a generic formal object of another generic unit @i<G>, and the instantiation containing the actual that occurs within the body of a generic unit @i<G> or within the body of a generic unit declared within the declarative region of the generic unit @i<G>, then the corresponding parameter or result type of the formal subprogram of @i<G> shall have a @fa<null_exclusion>;> @dby @xbullet<if the actual matching the @fa<formal_subprogram_declaration> statically denotes a generic formal subprogram of another generic unit @i<G>, and the instantiation containing the actual occurs within the body of a generic unit @i<G> or within the body of a generic unit declared within the declarative region of the generic unit @i<G>, then the corresponding parameter or result type of the formal subprogram of @i<G> shall have a @fa<null_exclusion>;>
!corrigendum 13.1(9/4)
!AI-0181-1
!AI-0222-1
@drepl A representation item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14). In addition, a representation item that directly specifies an aspect of a subtype or type shall appear after the type is completely defined (see 3.11.1). @dby A representation item or operational item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14).
!corrigendum 13.1(9.1/4)
!AI-0181-1
!AI-0222-1
@drepl An operational item that directly specifies an aspect of an entity shall appear before the entity is frozen (see 13.14). @dby An @fa<expression> or @fa<name> that freezes an entity shall not occur within an @fa<aspect_specification> that specifies a representation or operational aspect of that entity.
A representation aspect of a subtype or type shall not be specified (whether by a representation item or an @fa<aspect_specification>) before the type is completely defined (see 3.11.1).
!corrigendum 13.1.1(4/3)
!AI-0187-1
!AI-0285-1
@drepl @xcode<@fa<aspect_definition ::= name | expression | identifier>> @dby @xcode<@fa<aspect_definition>@fa< ::=>
@fa<name>@fa< | >@fa<expression>@fa< | >@fa<identifier>@fa< | >@fa<aggregate>>
!corrigendum 13.1.1(12/3)
!AI-0180-1
!AI-0220-1
@drepl If the associated declaration is for a subprogram or entry, the names of the formal parameters are directly visible within the @fa<aspect_definition>, as are certain attributes, as specified elsewhere in this International Standard for the identified aspect. If the associated declaration is a @fa<type_declaration>, within the @fa<aspect_definition> the names of any components are directly visible, and the name of the first subtype denotes the current instance of the type (see 8.6). If the associated declaration is a @fa<subtype_declaration>, within the @fa<aspect_definition> the name of the new subtype denotes the current instance of the subtype. @dby If the associated declaration is for a subprogram, entry, or access-to-subprogram type, the names of the formal parameters are directly visible within the @fa<aspect_definition>, as are certain attributes, as specified elsewhere in this International Standard for the identified aspect. If the associated declaration is a @fa<type_declaration>, within the @fa<aspect_definition> the names of any visible components, protected subprograms, and entries are directly visible, and the name of the first subtype denotes the current instance of the type (see 8.6). If the associated declaration is a @fa<subtype_declaration>, within the @fa<aspect_definition> the name of the new subtype denotes the current instance of the subtype.
!corrigendum 13.1.1(17/3)
!AI-0064-2
!AI-0194-1
@drepl There are no language-defined aspects that may be specified on a @fa<renaming_declaration>, a @fa<generic_formal_parameter_declaration>, a @fa<subunit>, a @fa<package_body>, a @fa<task_body>, a @fa<protected_body>, or a @fa<body_stub> other than a @fa<subprogram_body_stub>. @dby There are no language-defined aspects that may be specified on a @fa<renaming_declaration>, a @fa<subunit>, a @fa<package_body>, a @fa<task_body>, a @fa<protected_body>, an @fa<entry_body>, or a @fa<body_stub> other than a @fa<subprogram_body_stub>.
!corrigendum 13.1.1(18.3/4)
!AI-0206-1
!AI-0211-1
@drepl If a nonoverridable aspect is directly specified for a type @i<T>, then any explicit specification of that aspect for any other descendant of @i<T> shall be @i<confirming>; that is, the specified @fa<name> shall @i<match> the inherited aspect, meaning that the specified @fa<name> shall denote the same declarations as would the inherited @fa<name>. @dby If a nonoverridable aspect is directly specified for a type @i<T>, then any explicit specification of that aspect for any descendant of @i<T> (other than @i<T> itself) shall be @i<confirming>. In the case of an aspect whose value is a @fa<name>, this means that the specified @fa<name> shall @i<match> the inherited aspect in the sense that it shall denote the same declarations as would the inherited @fa<name>.
!corrigendum 13.1.1(18.6/4)
!AI-0206-1
!AI-0256-1
@drepl The Default_Iterator, Iterator_Element, Implicit_Dereference, Constant_Indexing, and Variable_Indexing aspects are nonoverridable. @dby The Default_Iterator, Iterator_Element, Implicit_Dereference, Constant_Indexing, Variable_Indexing, Max_Entry_Queue_Length, and No_Controlled_Parts aspects are nonoverridable.
!corrigendum 13.14(3/4)
!AI-0155-1
!AI-0168-1
@drepl The end of a @fa<declarative_part>, @fa<protected_body>, or a declaration of a library package or generic library package, causes @i<freezing> of each entity and profile declared within it, except for incomplete types. A @fa<proper_body>, @fa<body_stub>, or @fa<entry_body> causes freezing of each entity and profile declared before it within the same @fa<declarative_part> that is not an incomplete type; it only causes freezing of an incomplete type if the body is within the immediate scope of the incomplete type. @dby The end of a @fa<declarative_part>, @fa<protected_body>, or a declaration of a library package or generic library package, causes @i<freezing> of each entity and profile declared within it. A noninstance @fa<proper_body>, @fa<body_stub>, or @fa<entry_body> causes freezing of each entity and profile declared before it within the same @fa<declarative_part>.
!corrigendum A.3.2(32.5/3)
!AI-0004-1
!AI-0263-1
@dinsa @xhang<@xterm<Is_Space> True if Item is a character with position 32 (' ') or 160 (No_Break_Space).> @dinst @xhang<@xterm<Is_NFKC> True if Item could be present in a string normalized to Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017); this includes all characters except those with positions 160, 168, 170, 175, 178, 179, 180, 181, 184, 185, 186, 188, 189, and 190.>
!corrigendum A.3.5(51/3)
!AI-0004-1
!AI-0263-1
@dinsa @xindent<Returns True if the Wide_Character designated by Item is categorized as @fa<separator_space>, otherwise returns False.> @dinss @xcode<@b<function> Is_NFKC (Item : Wide_Character) @b<return> Boolean;>
@xindent<Returns True if the Wide_Character designated by Item could be present in a string normalized to Normalization Form KC (as defined by Clause 21 of ISO/IEC 10646:2017), otherwise returns False.>
!corrigendum B.5(21)
!AI-0058-1
!AI-0263-1
@drepl An implementation may add additional declarations to the Fortran interface packages. For example, the Fortran interface package for an implementation of Fortran 77 (ANSI X3.9-1978) that defines types like Integer*@i<n>, Real*@i<n>, Logical*@i<n>, and Complex*@i<n> may contain the declarations of types named Integer_Star_@i<n>, Real_Star_@i<n>, Logical_Star_@i<n>, and Complex_Star_@i<n>. (This convention should not apply to Character*@i<n>, for which the Ada analog is the constrained array subtype Fortran_Character (1..n).) Similarly, the Fortran interface package for an implementation of Fortran 90 that provides multiple kinds of intrinsic types, e.g. Integer (Kind=@i<n>), Real (Kind=@i<n>), Logical (Kind=@i<n>), Complex (Kind=@i<n>), and Character (Kind=@i<n>), may contain the declarations of types with the recommended names Integer_Kind_@i<n>, Real_Kind_@i<n>, Logical_Kind_@i<n>, Complex_Kind_@i<n>, and Character_Kind_@i<n>. @dby An implementation may add additional declarations to the Fortran interface packages. For example, declarations are permitted for the character types corresponding to Fortran character kinds 'ascii' and 'iso_10646', which in turn correspond to ISO/IEC 646:1991 and to UCS-4 as specified in ISO/IEC 10646:2017.
!corrigendum D.2.1(7/3)
!AI-0241-1
!AI-0279-1
@drepl A call of Yield is a task dispatching point. Yield is a potentially blocking operation (see 9.5.1). @dby A call of Yield is a task dispatching point.
If the Yield aspect has the value True, then a call to Yield is included within the body of the associated callable entity, and invoked immediately prior to returning from the body if and only if no other task dispatching points were encountered during the execution of the body.
!corrigendum D.4(7/2)
!AI-0163-1
!AI-0183-1
@drepl Two queuing policies, FIFO_Queuing and Priority_Queuing, are language defined. If no Queuing_Policy pragma applies to any of the program units comprising the partition, the queuing policy for that partition is FIFO_Queuing. The rules for this policy are specified in 9.5.3 and 9.7.1. @dby Three queuing policies, FIFO_Queuing, Ordered_FIFO_Queuing, and Priority_Queuing, are language defined. If no Queuing_Policy pragma applies to any of the program units comprising the partition, the queuing policy for that partition is FIFO_Queuing. The rules for the FIFO_Queuing policy are specified in 9.5.3 and 9.7.1.
The Ordered_FIFO_Queuing policy is defined as follows:
@xbullet<Calls are selected on a given entry queue in order of arrival.>
@xbullet<When more than one condition of an @fa<entry_barrier> of a protected object becomes True, and more than one of the respective queues is nonempty, the call that arrived first is selected.>
@xbullet<If the expiration time of two or more open @fa<delay_alternative>s is the same and no other @fa<accept_alternative>s are open, the @fa<sequence_of_statements> of the @fa<delay_alternative> that is first in textual order in the @fa<selective_accept> is executed.>
@xbullet<When more than one alternative of a @fa<selective_accept> is open and has queued calls, the alternative whose queue has the call that arrived first is selected.>
!corrigendum H.5(5/2)
!AI-0247-1
!AI-0267-1
@drepl An implementation is required to detect a potentially blocking operation within a protected operation, and to raise Program_Error (see 9.5.1). @dby An implementation is required to detect a potentially blocking operation that occurs during the execution of a protected operation or a parallel construct defined within a compilation unit to which the pragma applies, and to raise Program_Error (see 9.5).

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