Ada Programming/Libraries/GNAT.Sockets
Example
editwithAda.Text_IO;useAda.Text_IO;withGNAT.Sockets;useGNAT.Sockets;withAda.Streams;usetypeAda.Streams.Stream_Element_Count;procedureVcvisClient : Socket_Type; Address : Sock_Addr_Type; Channel : Stream_Access; Send : String := (1 => ASCII.CR, 2 => ASCII.LF, 3 => ASCII.CR, 4 => ASCII.LF); Offset : Ada.Streams.Stream_Element_Count; Data : Ada.Streams.Stream_Element_Array (1 .. 256);beginGNAT.Sockets.Initialize; -- initialize a specific package Create_Socket (Client); Address.Addr := Inet_Addr("203.66.88.89"); Address.Port := 80; Connect_Socket (Client, Address); Channel := Stream (Client); String'Write (Channel, "GET / HTTP/1.1" & Send);loopAda.Streams.Read (Channel.All, Data, Offset);exitwhenOffset = 0;forIin1 .. OffsetloopAda.Text_IO.Put (Character'Val (Data (I)));endloop;endloop;endVcv;
Specification
editwith Ada.Exceptions;
with Ada.Streams;
package GNAT.Sockets is
-- Sockets are designed to provide a consistent communication facility
-- between applications. This package provides an Ada-like interface
-- similar to that proposed as part of the BSD socket layer. This is a
-- system independent thick binding.
-- Here is a typical example of what you can do:
-- with GNAT.Sockets; use GNAT.Sockets;
--
-- with Ada.Text_IO;
-- with Ada.Exceptions; use Ada.Exceptions;
--
-- procedure PingPong is
--
-- Group : constant String := "239.255.128.128";
-- -- Multicast groupe: administratively scoped IP address
--
-- task Pong is
-- entry Start;
-- entry Stop;
-- end Pong;
--
-- task body Pong is
-- Address : Sock_Addr_Type;
-- Server : Socket_Type;
-- Socket : Socket_Type;
-- Channel : Stream_Access;
--
-- begin
-- accept Start;
--
-- -- Get an Internet address of a host (here the local host name).
-- -- Note that a host can have several addresses. Here we get
-- -- the first one which is supposed to be the official one.
--
-- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
--
-- -- Get a socket address that is an Internet address and a port
--
-- Address.Port := 5432;
--
-- -- The first step is to create a socket. Once created, this
-- -- socket must be associated to with an address. Usually only
-- -- a server (Pong here) needs to bind an address explicitly.
-- -- Most of the time clients can skip this step because the
-- -- socket routines will bind an arbitrary address to an unbound
-- -- socket.
--
-- Create_Socket (Server);
--
-- -- Allow reuse of local addresses.
--
-- Set_Socket_Option
-- (Server,
-- Socket_Level,
-- (Reuse_Address, True));
--
-- Bind_Socket (Server, Address);
--
-- -- A server marks a socket as willing to receive connect events.
--
-- Listen_Socket (Server);
--
-- -- Once a server calls Listen_Socket, incoming connects events
-- -- can be accepted. The returned Socket is a new socket that
-- -- represents the server side of the connection. Server remains
-- -- available to receive further connections.
--
-- Accept_Socket (Server, Socket, Address);
--
-- -- Return a stream associated to the connected socket.
--
-- Channel := Stream (Socket);
--
-- -- Force Pong to block
--
-- delay 0.2;
--
-- -- Receive and print message from client Ping.
--
-- declare
-- Message : String := String'Input (Channel);
--
-- begin
-- Ada.Text_IO.Put_Line (Message);
--
-- -- Send same message to server Pong.
--
-- String'Output (Channel, Message);
-- end;
--
-- Close_Socket (Server);
-- Close_Socket (Socket);
--
-- -- Part of the multicast example
--
-- -- Create a datagram socket to send connectionless, unreliable
-- -- messages of a fixed maximum length.
--
-- Create_Socket (Socket, Family_Inet, Socket_Datagram);
--
-- -- Allow reuse of local addresses.
--
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
--
-- -- Join a multicast group.
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
--
-- -- Controls the live time of the datagram to avoid it being
-- -- looped forever due to routing errors. Routers decrement
-- -- the TTL of every datagram as it traverses from one network
-- -- to another and when its value reaches 0 the packet is
-- -- dropped. Default is 1.
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_TTL, 1));
--
-- -- Want the data you send to be looped back to your host.
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_Loop, True));
--
-- -- If this socket is intended to receive messages, bind it to a
-- -- given socket address.
--
-- Address.Addr := Any_Inet_Addr;
-- Address.Port := 55505;
--
-- Bind_Socket (Socket, Address);
--
-- -- If this socket is intended to send messages, provide the
-- -- receiver socket address.
--
-- Address.Addr := Inet_Addr (Group);
-- Address.Port := 55506;
--
-- Channel := Stream (Socket, Address);
--
-- -- Receive and print message from client Ping.
--
-- declare
-- Message : String := String'Input (Channel);
--
-- begin
--
-- -- Get the address of the sender.
--
-- Address := Get_Address (Channel);
-- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
--
-- -- Send same message to server Pong.
--
-- String'Output (Channel, Message);
-- end;
--
-- Close_Socket (Socket);
--
-- accept Stop;
--
-- exception when E : others =>
-- Ada.Text_IO.Put_Line
-- (Exception_Name (E) & ": " & Exception_Message (E));
-- end Pong;
--
-- task Ping is
-- entry Start;
-- entry Stop;
-- end Ping;
--
-- task body Ping is
-- Address : Sock_Addr_Type;
-- Socket : Socket_Type;
-- Channel : Stream_Access;
--
-- begin
-- accept Start;
--
-- -- See comments in Ping section for the first steps.
--
-- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
-- Address.Port := 5432;
-- Create_Socket (Socket);
--
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
--
-- -- Force Pong to block
--
-- delay 0.2;
--
-- -- If the client's socket is not bound, Connect_Socket will
-- -- bind to an unused address. The client uses Connect_Socket to
-- -- create a logical connection between the client's socket and
-- -- a server's socket returned by Accept_Socket.
--
-- Connect_Socket (Socket, Address);
--
-- Channel := Stream (Socket);
--
-- -- Send message to server Pong.
--
-- String'Output (Channel, "Hello world");
--
-- -- Force Ping to block
--
-- delay 0.2;
--
-- -- Receive and print message from server Pong.
--
-- Ada.Text_IO.Put_Line (String'Input (Channel));
-- Close_Socket (Socket);
--
-- -- Part of multicast example. Code similar to Pong's one.
--
-- Create_Socket (Socket, Family_Inet, Socket_Datagram);
--
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_TTL, 1));
--
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_Loop, True));
--
-- Address.Addr := Any_Inet_Addr;
-- Address.Port := 55506;
--
-- Bind_Socket (Socket, Address);
--
-- Address.Addr := Inet_Addr (Group);
-- Address.Port := 55505;
--
-- Channel := Stream (Socket, Address);
--
-- -- Send message to server Pong.
--
-- String'Output (Channel, "Hello world");
--
-- -- Receive and print message from server Pong.
--
-- declare
-- Message : String := String'Input (Channel);
--
-- begin
-- Address := Get_Address (Channel);
-- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
-- end;
--
-- Close_Socket (Socket);
--
-- accept Stop;
--
-- exception when E : others =>
-- Ada.Text_IO.Put_Line
-- (Exception_Name (E) & ": " & Exception_Message (E));
-- end Ping;
--
-- begin
-- -- Indicate whether the thread library provides process
-- -- blocking IO. Basically, if you are not using FSU threads
-- -- the default is ok.
--
-- Initialize (Process_Blocking_IO => False);
-- Ping.Start;
-- Pong.Start;
-- Ping.Stop;
-- Pong.Stop;
-- Finalize;
-- end PingPong;
procedure Initialize (Process_Blocking_IO : Boolean := False);
-- Initialize must be called before using any socket routines. If
-- the thread library provides process blocking IO - basically
-- with FSU threads - GNAT.Sockets should be initialized with a
-- value of True to simulate thread blocking IO. Further calls to
-- Initialize will be ignored.
procedure Finalize;
-- After Finalize is called it is not possible to use any routines
-- exported in by this package. This procedure is idempotent.
type Socket_Type is private;
-- Sockets are used to implement a reliable bi-directional
-- point-to-point, stream-based connections between
-- hosts. No_Socket provides a special value to denote
-- uninitialized sockets.
No_Socket : constant Socket_Type;
Socket_Error : exception;
-- There is only one exception in this package to deal with an
-- error during a socket routine. Once raised, its message
-- contains a string describing the error code.
function Image (Socket : Socket_Type) return String;
-- Return a printable string for Socket
function To_C (Socket : Socket_Type) return Integer;
-- Return a file descriptor to be used by external subprograms
-- especially the C functions that are not yet interfaced in this
-- package.
type Family_Type is (Family_Inet, Family_Inet6);
-- Address family (or protocol family) identifies the
-- communication domain and groups protocols with similar address
-- formats. IPv6 will soon be supported.
type Mode_Type is (Socket_Stream, Socket_Datagram);
-- Stream sockets provide connection-oriented byte
-- streams. Datagram sockets support unreliable connectionless
-- message based communication.
type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write);
-- When a process closes a socket, the policy is to retain any
-- data queued until either a delivery or a timeout expiration (in
-- this case, the data are discarded). A finer control is
-- available through shutdown. With Shut_Read, no more data can be
-- received from the socket. With_Write, no 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.
Any_Port : constant Port_Type;
No_Port : constant Port_Type;
type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
-- An Internet address depends on an address family (IPv4 contains
-- 4 octets and Ipv6 contains 16 octets). Any_Inet_Address is a
-- special value treated like a wildcard enabling all addresses.
-- No_Inet_Addr provides a special value to denote uninitialized
-- inet addresses.
Any_Inet_Addr : constant Inet_Addr_Type;
No_Inet_Addr : constant Inet_Addr_Type;
type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
Addr : Inet_Addr_Type (Family);
Port : Port_Type;
end record;
-- Socket addresses fully define a socket connection with a
-- protocol family, an Internet address and a port. No_Sock_Addr
-- provides a special value for uninitialized socket addresses.
No_Sock_Addr : constant Sock_Addr_Type;
function Image (Value : Inet_Addr_Type) return String;
-- Return an image of an Internet address. IPv4 notation consists
-- in 4 octets in decimal format separated by dots. IPv6 notation
-- consists in 16 octets in hexadecimal format separated by
-- colons (and possibly dots).
function Image (Value : Sock_Addr_Type) return String;
-- Return inet address image and port image separated by a colon.
function Inet_Addr (Image : String) return Inet_Addr_Type;
-- Convert address image from numbers-and-dots notation into an
-- inet address.
-- Host entries provide a complete information on a given host:
-- the official name, an array of alternative names or aliases and
-- array of network addresses.
type Host_Entry_Type
(Aliases_Length, Addresses_Length : Natural) is private;
function Official_Name (E : Host_Entry_Type) return String;
-- Return official name in host entry
function Aliases_Length (E : Host_Entry_Type) return Natural;
-- Return number of aliases in host entry
function Addresses_Length (E : Host_Entry_Type) return Natural;
-- Return number of addresses in host entry
function Aliases
(E : Host_Entry_Type;
N : Positive := 1)
return String;
-- Return N'th aliases in host entry. The first index is 1.
function Addresses
(E : Host_Entry_Type;
N : Positive := 1)
return Inet_Addr_Type;
-- Return N'th addresses in host entry. The first index is 1.
Host_Error : exception;
-- Exception raised by the two following procedures. Once raised,
-- its message contains a string describing the error code. This
-- exception is raised when an host entry can not be retrieved.
function Get_Host_By_Address
(Address : Inet_Addr_Type;
Family : Family_Type := Family_Inet)
return Host_Entry_Type;
-- Return host entry structure for the given inet address
function Get_Host_By_Name
(Name : String)
return Host_Entry_Type;
-- Return host entry structure for the given host name
function Host_Name return String;
-- Return the name of the current host
-- Errors are described by an enumeration type. There is only one
-- exception Socket_Error in this package to deal with an error
-- during a socket routine. Once raised, its message contains the
-- error code between brackets and a string describing the error code.
-- The name of the enumeration constant documents the error condition.
type Error_Type is
(Permission_Denied,
Address_Already_In_Use,
Cannot_Assign_Requested_Address,
Address_Family_Not_Supported_By_Protocol,
Operation_Already_In_Progress,
Bad_File_Descriptor,
Connection_Refused,
Bad_Address,
Operation_Now_In_Progress,
Interrupted_System_Call,
Invalid_Argument,
Input_Output_Error,
Transport_Endpoint_Already_Connected,
Message_Too_Long,
Network_Is_Unreachable,
No_Buffer_Space_Available,
Protocol_Not_Available,
Transport_Endpoint_Not_Connected,
Operation_Not_Supported,
Protocol_Not_Supported,
Socket_Type_Not_Supported,
Connection_Timed_Out,
Resource_Temporarily_Unavailable,
Unknown_Host,
Host_Name_Lookup_Failure,
No_Address_Associated_With_Name,
Unknown_Server_Error,
Cannot_Resolve_Error);
-- Get_Socket_Options and Set_Socket_Options manipulate options
-- associated with a socket. Options may exist at multiple
-- protocol levels in the communication stack. Socket_Level is the
-- uppermost socket level.
type Level_Type is (
Socket_Level,
IP_Protocol_For_IP_Level,
IP_Protocol_For_UDP_Level,
IP_Protocol_For_TCP_Level);
-- There are several options available to manipulate sockets. Each
-- option has a name and several values available. Most of the
-- time, the value is a boolean to enable or disable this option.
type Option_Name is (
Keep_Alive, -- Enable sending of keep-alive messages
Reuse_Address, -- Allow bind to reuse local address
Broadcast, -- Enable datagram sockets to recv/send broadcast packets
Send_Buffer, -- Set/get the maximum socket send buffer in bytes
Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
Linger, -- Shutdown wait for msg to be sent or timeout occur
Error, -- Get and clear the pending socket error
No_Delay, -- Do not delay send to coalesce packets (TCP_NODELAY)
Add_Membership, -- Join a multicast group
Drop_Membership, -- Leave a multicast group
Multicast_TTL, -- Indicates the time-to-live of sent multicast packets
Multicast_Loop); -- Sent multicast packets are looped to the local socket
type Option_Type (Name : Option_Name := Keep_Alive) is record
case Name is
when Keep_Alive |
Reuse_Address |
Broadcast |
Linger |
No_Delay |
Multicast_Loop =>
Enabled : Boolean;
case Name is
when Linger =>
Seconds : Natural;
when others =>
null;
end case;
when Send_Buffer |
Receive_Buffer =>
Size : Natural;
when Error =>
Error : Error_Type;
when Add_Membership |
Drop_Membership =>
Multiaddr : Inet_Addr_Type;
Interface : Inet_Addr_Type;
when Multicast_TTL =>
Time_To_Live : Natural;
end case;
end record;
-- There are several controls available to manipulate
-- sockets. Each option has a name and several values available.
-- These controls differ from the socket options in that they are
-- not specific to sockets but are available for any device.
type Request_Name is (
Non_Blocking_IO, -- Cause a caller not to wait on blocking operations.
N_Bytes_To_Read); -- Return the number of bytes available to read
type Request_Type (Name : Request_Name := Non_Blocking_IO) is record
case Name is
when Non_Blocking_IO =>
Enabled : Boolean;
when N_Bytes_To_Read =>
Size : Natural;
end case;
end record;
procedure Create_Socket
(Socket : out Socket_Type;
Family : Family_Type := Family_Inet;
Mode : Mode_Type := Socket_Stream);
-- Create an endpoint for communication. Raise Socket_Error on error.
procedure Accept_Socket
(Server : Socket_Type;
Socket : out Socket_Type;
Address : out Sock_Addr_Type);
-- Extract the first connection request on the queue of pending
-- connections, creates a new connected socket with mostly the
-- same properties as Server, and allocates a new socket. The
-- returned Address is filled in with the address of the
-- connection. Raise Socket_Error on error.
procedure Bind_Socket
(Socket : Socket_Type;
Address : Sock_Addr_Type);
-- Once a socket is created, assign a local address to it. Raise
-- Socket_Error on error.
procedure Close_Socket (Socket : Socket_Type);
-- Close a socket and more specifically a non-connected socket.
procedure Connect_Socket
(Socket : Socket_Type;
Server : in out Sock_Addr_Type);
-- Make a connection to another socket which has the address of
-- Server. Raise Socket_Error on error.
procedure Control_Socket
(Socket : Socket_Type;
Request : in out Request_Type);
-- Obtain or set parameter values that control the socket. This
-- control differs from the socket options in that they are not
-- specific to sockets but are available for any device.
function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type;
-- Return the peer or remote socket address of a socket. Raise
-- Socket_Error on error.
function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type;
-- Return the local or current socket address of a socket. Raise
-- Socket_Error on error.
function Get_Socket_Option
(Socket : Socket_Type;
Level : Level_Type := Socket_Level;
Name : Option_Name)
return Option_Type;
-- Get the options associated with a socket. Raise Socket_Error on
-- error.
procedure Listen_Socket
(Socket : Socket_Type;
Length : Positive := 15);
-- To accept connections, a socket is first created with
-- Create_Socket, a willingness to accept incoming connections and
-- a queue Length for incoming connections are specified. Raise
-- Socket_Error on error.
procedure Receive_Socket
(Socket : Socket_Type;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
-- Receive message from Socket. Last is the index value such that
-- Item (Last) is the last character assigned. Note that Last is
-- set to Item'First - 1 when the socket has been closed by
-- peer. This is not an error and no exception is raised. Raise
-- Socket_Error on error.
procedure Receive_Socket
(Socket : Socket_Type;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset;
From : out Sock_Addr_Type);
-- Receive message from Socket. If Socket is not
-- connection-oriented, the source address From of the message is
-- filled in. Last is the index value such that Item (Last) is the
-- last character assigned. Raise Socket_Error on error.
function Resolve_Exception
(Occurrence : Ada.Exceptions.Exception_Occurrence)
return Error_Type;
-- When Socket_Error or Host_Error are raised, the exception
-- message contains the error code between brackets and a string
-- describing the error code. Resolve_Error extracts the error
-- code from an exception message and translate it into an
-- enumeration value.
procedure Send_Socket
(Socket : Socket_Type;
Item : Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
-- Transmit a message to another socket. Note that Last is set to
-- Item'First when socket has been closed by peer. This is not an
-- error and no exception is raised. Raise Socket_Error on error;
procedure Send_Socket
(Socket : Socket_Type;
Item : Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset;
To : Sock_Addr_Type);
-- Transmit a message to another socket. The address is given by
-- To. Raise Socket_Error on error;
procedure Set_Socket_Option
(Socket : Socket_Type;
Level : Level_Type := Socket_Level;
Option : Option_Type);
-- Manipulate socket options. Raise Socket_Error on error.
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.
type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
-- Same interface as Ada.Streams.Stream_IO
function Stream
(Socket : Socket_Type)
return Stream_Access;
-- Associate a stream with a stream-based socket that is already
-- connected.
function Stream
(Socket : Socket_Type;
Send_To : Sock_Addr_Type)
return Stream_Access;
-- Associate a stream with a datagram-based socket that is already
-- bound. Send_To is the socket address to which messages are
-- being sent.
function Get_Address
(Stream : Stream_Access)
return Sock_Addr_Type;
-- Return the socket address from which the last message was
-- received.
type Socket_Set_Type is private;
-- This type allows to manipulate sets of sockets. It allows to
-- wait for events on multiple endpoints at one time. This is an
-- access type on a system dependent structure. To avoid memory
-- leaks it is highly recommended to clean the access value with
-- procedure Empty.
procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type);
-- Remove Socket from Item
procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
-- Insert Socket into Item
procedure Empty (Item : in out Socket_Set_Type);
-- Remove all Sockets from Item and deallocate internal data
function Is_Empty
(Item : Socket_Set_Type)
return Boolean;
-- Return True if Item is empty
function Is_Set
(Item : Socket_Set_Type;
Socket : Socket_Type)
return Boolean;
-- Return True if Socket is present in Item
-- C select() waits for a number of file descriptors to change
-- status. Usually, three independent sets of descriptors are
-- watched (read, write and exception). A timeout gives an upper
-- bound on the amount of time elapsed before select returns.
-- This function blocks until an event occurs. On some platforms,
-- C select can block the full process.
--
-- 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 in purpose.
-- The timeout parameter allows the user to have the behaviour he
-- wants. Abort_Selector allows to abort safely a Check_Selector
-- that is blocked forever. A special file descriptor 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. The user must
-- call Close_Selector to discard this special file. A reason to
-- abort a select operation is typically to add a socket in one of
-- the socket sets when the timeout is set to forever.
Forever : constant Duration;
type Selector_Type is limited private;
type Selector_Access is access all Selector_Type;
procedure Create_Selector (Selector : out Selector_Type);
-- Create a new selector
procedure Close_Selector (Selector : in out Selector_Type);
-- Close Selector and all internal descriptors associated
type Selector_Status is (Completed, Expired, Aborted);
procedure Check_Selector
(Selector : in out Selector_Type;
R_Socket_Set : in out Socket_Set_Type;
W_Socket_Set : in out Socket_Set_Type;
Status : out Selector_Status;
Timeout : Duration := Forever);
-- Return when one Socket in R_Socket_Set has some data to be read
-- or if one Socket in W_Socket_Set is ready to receive some
-- data. In these cases Status is set to Completed and sockets
-- that are ready are set in 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. As this procedure
-- returns when Timeout occurs, it is a design choice to keep this
-- procedure process blocking. Note that a Timeout of 0.0 returns
-- immediatly.
procedure Abort_Selector (Selector : Selector_Type);
-- Send an abort signal to the selector.
private
type Socket_Type is new Integer;
No_Socket : constant Socket_Type := -1;
Forever : constant Duration := Duration'Last;
type Selector_Type is limited record
R_Sig_Socket : Socket_Type;
W_Sig_Socket : Socket_Type;
In_Progress : Boolean := False;
end record;
-- The two signalling sockets are used to abort a select
-- operation.
type Socket_Set_Record;
type Socket_Set_Type is access all Socket_Set_Record;
subtype Inet_Addr_Comp_Type is Natural range 0 .. 255;
-- Octet for Internet address
type Inet_Addr_VN_Type is array (Natural range <>) of Inet_Addr_Comp_Type;
subtype Inet_Addr_V4_Type is Inet_Addr_VN_Type (1 .. 4);
subtype Inet_Addr_V6_Type is Inet_Addr_VN_Type (1 .. 16);
type Inet_Addr_Type (Family : Family_Type := Family_Inet) is record
case Family is
when Family_Inet =>
Sin_V4 : Inet_Addr_V4_Type := (others => 0);
when Family_Inet6 =>
Sin_V6 : Inet_Addr_V6_Type := (others => 0);
end case;
end record;
Any_Port : constant Port_Type := 0;
No_Port : constant Port_Type := 0;
Any_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0));
No_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0));
No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
Max_Host_Name_Length : constant := 64;
-- The constant MAXHOSTNAMELEN is usually set to 64
subtype Host_Name_Index is Natural range 1 .. Max_Host_Name_Length;
type Host_Name_Type
(Length : Host_Name_Index := Max_Host_Name_Length)
is record
Name : String (1 .. Length);
end record;
-- We need fixed strings to avoid access types in host entry type
type Host_Name_Array is array (Natural range <>) of Host_Name_Type;
type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type;
type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
Official : Host_Name_Type;
Aliases : Host_Name_Array (1 .. Aliases_Length);
Addresses : Inet_Addr_Array (1 .. Addresses_Length);
end record;
end GNAT.Sockets;
See also
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