type Selector_Access is access all Selector_Type;
-- Selector objects are used to wait for i/o events to occur on sockets
+ Null_Selector : constant Selector_Type;
+ -- The Null_Selector can be used in place of a normal selector without
+ -- having to call Create_Selector if the use of Abort_Selector is not
+ -- required.
+
-- Timeval_Duration is a subtype of Standard.Duration because the full
-- range of Standard.Duration cannot be represented in the equivalent C
-- structure. Moreover, negative values are not allowed to avoid system
-- more data can be transmitted. Neither transmission nor reception can be
-- performed with Shut_Read_Write.
- type Port_Type is new Natural;
- -- Classical port definition. No_Port provides a special value to
- -- denote uninitialized port. Any_Port provides a special value
- -- enabling all ports.
+ type Port_Type is range 0 .. 16#ffff#;
+ -- TCP/UDP port number
Any_Port : constant Port_Type;
- No_Port : constant Port_Type;
+ -- All ports
+
+ No_Port : constant Port_Type;
+ -- Uninitialized port number
type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
-- An Internet address depends on an address family (IPv4 contains 4 octets
Count : out Ada.Streams.Stream_Element_Count;
Flags : Request_Flag_Type := No_Request_Flag);
-- Transmit data gathered from the set of vector elements Vector to a
- -- socket. Count is set to the count of transmitted stream elements.
- -- Flags allow control over transmission.
+ -- socket. Count is set to the count of transmitted stream elements. Flags
+ -- allow control over transmission.
procedure Set_Socket_Option
(Socket : Socket_Type;
procedure Shutdown_Socket
(Socket : Socket_Type;
How : Shutmode_Type := Shut_Read_Write);
- -- Shutdown a connected socket. If How is Shut_Read, further receives will
- -- be disallowed. If How is Shut_Write, further sends will be disallowed.
- -- If how is Shut_Read_Write, further sends and receives will be
- -- disallowed.
+ -- Shutdown a connected socket. If How is Shut_Read further receives will
+ -- be disallowed. If How is Shut_Write further sends will be disallowed.
+ -- If How is Shut_Read_Write further sends and receives will be disallowed.
type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
-- Same interface as Ada.Streams.Stream_IO
procedure Free is new Ada.Unchecked_Deallocation
(Ada.Streams.Root_Stream_Type'Class, Stream_Access);
- -- Destroy a stream created by one of the Stream functions above,
- -- releasing the corresponding resources. The user is responsible for
- -- calling this subprogram when the stream is not needed anymore.
+ -- Destroy a stream created by one of the Stream functions above, releasing
+ -- the corresponding resources. The user is responsible for calling this
+ -- subprogram when the stream is not needed anymore.
type Socket_Set_Type is limited private;
-- This type allows to manipulate sets of sockets. It allows to wait for
-- can block the full process (not just the calling thread).
--
-- Check_Selector provides the very same behaviour. The only difference is
- -- that it does not watch for exception events. Note that on some
- -- platforms it is kept process blocking on purpose. The timeout parameter
- -- allows the user to have the behaviour he wants. Abort_Selector allows
- -- to safely abort a blocked Check_Selector call. A special socket
- -- is opened by Create_Selector and included in each call to
- -- Check_Selector. Abort_Selector causes an event to occur on this
- -- descriptor in order to unblock Check_Selector. Note that each call to
- -- Abort_Selector will cause exactly one call to Check_Selector to return
- -- with Aborted status. The special socket created by Create_Selector is
- -- closed when Close_Selector is called.
+ -- that it does not watch for exception events. Note that on some platforms
+ -- it is kept process blocking on purpose. The timeout parameter allows the
+ -- user to have the behaviour he wants. Abort_Selector allows to safely
+ -- abort a blocked Check_Selector call. A special socket is opened by
+ -- Create_Selector and included in each call to Check_Selector.
+ --
+ -- Abort_Selector causes an event to occur on this descriptor in order to
+ -- unblock Check_Selector. Note that each call to Abort_Selector will cause
+ -- exactly one call to Check_Selector to return with Aborted status. The
+ -- special socket created by Create_Selector is closed when Close_Selector
+ -- is called.
+ --
-- A typical case where it is useful to abort a Check_Selector operation is
-- the situation where a change to the monitored sockets set must be made.
procedure Create_Selector (Selector : out Selector_Type);
- -- Create a new selector
+ -- Initialize (open) a new selector
procedure Close_Selector (Selector : in out Selector_Type);
-- Close Selector and all internal descriptors associated; deallocate any
-- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
-- ready after a Timeout expiration. Status is set to Aborted if an abort
-- signal has been received while checking socket status.
+ --
-- Note that two different Socket_Set_Type objects must be passed as
-- R_Socket_Set and W_Socket_Set (even if they denote the same set of
-- Sockets), or some event may be lost.
- -- Socket_Error is raised when the select(2) system call returns an
- -- error condition, or when a read error occurs on the signalling socket
- -- used for the implementation of Abort_Selector.
+ --
+ -- Socket_Error is raised when the select(2) system call returns an error
+ -- condition, or when a read error occurs on the signalling socket used for
+ -- the implementation of Abort_Selector.
procedure Check_Selector
(Selector : Selector_Type;
-- different objects.
procedure Abort_Selector (Selector : Selector_Type);
- -- Send an abort signal to the selector
+ -- Send an abort signal to the selector. The Selector may not be the
+ -- Null_Selector.
type Fd_Set is private;
-- ??? This type must not be used directly, it needs to be visible because
type Socket_Type is new Integer;
No_Socket : constant Socket_Type := -1;
- type Selector_Type is limited record
- R_Sig_Socket : Socket_Type := No_Socket;
- W_Sig_Socket : Socket_Type := No_Socket;
- -- Signalling sockets used to abort a select operation
+ -- A selector is either a null selector, which is always "open" and can
+ -- never be aborted, or a regular selector, which is created "closed",
+ -- becomes "open" when Create_Selector is called, and "closed" again when
+ -- Close_Selector is called.
+
+ type Selector_Type (Is_Null : Boolean := False) is limited record
+ case Is_Null is
+ when True =>
+ null;
+
+ when False =>
+ R_Sig_Socket : Socket_Type := No_Socket;
+ W_Sig_Socket : Socket_Type := No_Socket;
+ -- Signalling sockets used to abort a select operation
+
+ end case;
end record;
pragma Volatile (Selector_Type);
+ Null_Selector : constant Selector_Type := (Is_Null => True);
+
type Fd_Set is
new System.Storage_Elements.Storage_Array (1 .. SOSC.SIZEOF_fd_set);
for Fd_Set'Alignment use Interfaces.C.long'Alignment;
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