E.2.2 Remote Types Library Units
1
A remote types library unit supports the definition
of types intended for use in communication between active partitions.
Syntax
2
The
form of a
pragma
Remote_Types is as follows:
3
pragma Remote_Types[(
library_unit_name)];
Legality Rules
4
A
remote types library unit is a library unit to which the pragma
Remote_Types applies. The following restrictions apply to the declaration
of such a library unit:
5
- it shall be preelaborable;
6
- it shall depend semantically only
on declared pure, shared passive, or other remote types library units;
7
- it shall not contain the declaration
of any variable within the visible part of the library unit;
8/2
- the full view of each type declared
in the visible part of the library unit that has any available stream
attributes shall support external streaming (see 13.13.2).
9/1
An
access type declared in the visible part of a remote types or remote
call interface library unit is called a
remote access type.
Such
a type shall be:
9.1/1
- an access-to-subprogram type, or
9.2/1
- a general access type that designates
a class-wide limited private type or a class-wide private type extension
all of whose ancestors are either private type extensions or limited
private types.
9.3/1
A type that is derived from a remote access type
is also a remote access type.
10
The following restrictions
apply to the use of a remote access-to-subprogram type:
11/2
- A value of a remote access-to-subprogram
type shall be converted only to or from another (subtype-conformant)
remote access-to-subprogram type;
12
- The prefix
of an Access attribute_reference
that yields a value of a remote access-to-subprogram type shall statically
denote a (subtype-conformant) remote subprogram.
13
The following restrictions
apply to the use of a remote access-to-class-wide type:
14/2
- The primitive subprograms of the corresponding
specific limited private type shall only have access parameters if they
are controlling formal parameters; each non-controlling formal parameter
shall support external streaming (see 13.13.2);
15
- A value of a remote access-to-class-wide
type shall be explicitly converted only to another remote access-to-class-wide
type;
16/1
- A value of a remote access-to-class-wide
type shall be dereferenced (or implicitly converted to an anonymous access
type) only as part of a dispatching call where the value designates a
controlling operand of the call (see E.4, “Remote
Subprogram Calls”).
17/2
- The Storage_Pool attribute is not
defined for a remote access-to-class-wide type; the expected type for
an allocator
shall not be a remote access-to-class-wide type. A remote access-to-class-wide
type shall not be an actual parameter for a generic formal access type.
The Storage_Size attribute of a remote access-to-class-wide type yields
0; it is not allowed in an attribute_definition_clause.
18
5 A remote types library unit need not
be pure, and the types it defines may include levels of indirection implemented
by using access types. User-specified Read and Write attributes (see
13.13.2) provide for sending values of
such a type between active partitions, with Write marshalling the representation,
and Read unmarshalling any levels of indirection.