E.4.1 Pragma Asynchronous
[This subclause introduces the pragma Asynchronous
which allows a remote subprogram call to return prior to completion of
the execution of the corresponding remote subprogram body.]
Syntax
The form of a
pragma
Asynchronous is as follows:
Legality Rules
The
local_name
of a pragma Asynchronous shall denote either:
One or more remote procedures; the formal parameters
of the procedure(s) shall all be of mode in;
The first subtype of a remote access-to-procedure
type; the formal parameters of the designated profile of the type shall
all be of mode in;
The first subtype of a remote access-to-class-wide
type.
Static Semantics
{representation pragma
(Asynchronous) [partial]} {pragma,
representation (Asynchronous) [partial]} A
pragma Asynchronous is a representation pragma. When applied to a type,
it specifies the type-related
asynchronous aspect of the type.
Dynamic Semantics
{remote procedure
call (asynchronous)} {asynchronous
(remote procedure call)} A remote call
is
asynchronous if it is a call to a procedure, or a call through
a value of an access-to-procedure type, to which a pragma Asynchronous
applies. In addition, if a pragma Asynchronous applies to a remote access-to-class-wide
type, then a dispatching call on a procedure with a controlling operand
designated by a value of the type is asynchronous if the formal parameters
of the procedure are all of mode
in.
Implementation Requirements
Asynchronous remote procedure calls shall be implemented
such that the corresponding body executes at most once as a result of
the call.
To be honest: It is not clear that this
rule can be tested or even defined formally.
Sponsored by Ada-Europe