9.5.2 Entries and Accept Statements
Name Resolution Rules
in a task declaration shall not contain a specification for an access
parameter (see 3.10
if the overriding_indicator
is not overriding
, then the entry shall not implement any inherited
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
In the entry_body
for an entry family, the entry_index_specification
declares a named constant whose subtype is the entry index subtype defined
by the corresponding entry_declaration
the value of the named entry index
which entry of the family was called.
The actions to be performed when an entry is called
are specified by the corresponding accept_statement
(if any) for an entry of a task unit, and by the corresponding entry_body
for an entry of a protected unit.
The above interaction between
a calling task and an accepting task is called a rendezvous
a rendezvous, the two tasks continue their execution independently.
24 A task entry has corresponding accept_statements
(zero or more), whereas a protected entry has a corresponding entry_body
27 The condition
in the entry_barrier
may reference anything visible except the formal parameters of the entry.
This includes the entry index (if any), the components (including discriminants)
of the protected object, the Count attribute of an entry of that protected
object, and data global to the protected unit.
The restriction against referencing the formal parameters
within an entry_barrier
ensures that all calls of the same entry see the same barrier value.
If it is necessary to look at the parameters of an entry call before
deciding whether to handle it, the entry_barrier
can be “when
True” and the caller can be requeued
(on some private entry) when its parameters indicate that it cannot be
Examples of entry
entry Read(V : out Item);
entry Request(Level)(D : Item); -- a family of entries
Examples of accept
accept Read(V : out Item) do
V := Local_Item;
accept Request(Low)(D : Item) do
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