[Ada] GNAT.Sockets: remove default level in Get/Set_Socket_Option

2019-07-08  Dmitriy Anisimkov  <anisimko@adacore.com>

gcc/ada/

	* libgnat/g-socket.ads, libgnat/g-socket.adb: Improve
	documentation.
	(Get_Socket_Option, Set_Socket_Option): Remove default value for
	the Level formal.

From-SVN: r273198

gcc/ada/ChangeLog

+2019-07-08  Dmitriy Anisimkov  <anisimko@adacore.com>
+
+	* libgnat/g-socket.ads, libgnat/g-socket.adb: Improve
+	documentation.
+	(Get_Socket_Option, Set_Socket_Option): Remove default value for
+	the Level formal.
+
 2019-07-08  Ed Schonberg  <schonberg@adacore.com>
 
 	* sem_ch13.adb (Check_Aspect_At_End_Of_Declarations): For an

gcc/ada/libgnat/g-socket.adb

@@ -1369,7 +1369,7 @@ package body GNAT.Sockets is
 
    function Get_Socket_Option
      (Socket  : Socket_Type;
-      Level   : Level_Type := Socket_Level;
+      Level   : Level_Type;
       Name    : Option_Name;
       Optname : Interfaces.C.int := -1) return Option_Type
    is
@@ -2539,7 +2539,7 @@ package body GNAT.Sockets is
 
    procedure Set_Socket_Option
      (Socket : Socket_Type;
-      Level  : Level_Type := Socket_Level;
+      Level  : Level_Type;
       Option : Option_Type)
    is
       use type C.unsigned;

gcc/ada/libgnat/g-socket.ads

@@ -775,34 +775,113 @@ package GNAT.Sockets is
       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.
+   --  has a name and several values available. Most of the time, the value
+   --  is a boolean to enable or disable this option. Each socket option is
+   --  provided with an appropriate C name taken from the sockets API comments.
+   --  The C name can be used to find a detailed description in the OS-specific
+   --  documentation. The options are grouped by main Level_Type value, which
+   --  can be used together with this option in calls to the Set_Socket_Option
+   --  and Get_Socket_Option routines. Note that some options can be used with
+   --  more than one level.
 
    type Option_Name is
      (Generic_Option,
-      Keep_Alive,          -- Enable sending of keep-alive messages
-      Reuse_Address,       -- Allow bind to reuse local address
-      Broadcast,           -- Enable datagram sockets to recv/send broadcasts
-      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 data (TCP_NODELAY)
-      Add_Membership_V4,   -- Join a multicast group
-      Add_Membership_V6,   -- Idem for IPv6 socket
-      Drop_Membership_V4,  -- Leave a multicast group
-      Drop_Membership_V6,  -- Idem for IPv6 socket
-      Multicast_If_V4,     -- Set default out interface for multicast packets
-      Multicast_If_V6,     -- Idem for IPv6 socket
-      Multicast_Loop_V4,   -- Sent multicast packets are looped to local socket
-      Multicast_Loop_V6,   -- Idem for IPv6 socket
-      Multicast_TTL,       -- Set the time-to-live of sent multicast packets
-      Multicast_Hops,      -- Set the multicast hop limit for the IPv6 socket
-      Receive_Packet_Info, -- Receive low level packet info as ancillary data
-      Send_Timeout,        -- Set timeout value for output
-      Receive_Timeout,     -- Set timeout value for input
-      IPv6_Only,           -- Restricted to IPv6 communications only
-      Busy_Polling);       -- Set busy polling mode
+      --  Can be used to set/get any socket option via an OS-specific option
+      --  code with an integer value.
+
+      ------------------
+      -- Socket_Level --
+      ------------------
+
+      Keep_Alive,      -- SO_KEEPALIVE
+      --  Enable sending of keep-alive messages on connection-oriented sockets
+
+      Reuse_Address,   -- SO_REUSEADDR
+      --  Enable binding to an address and port already in use
+
+      Broadcast,       -- SO_BROADCAST
+      --  Enable sending broadcast datagrams on the socket
+
+      Send_Buffer,     -- SO_SNDBUF
+      --  Set/get the maximum socket send buffer in bytes
+
+      Receive_Buffer,  -- SO_RCVBUF
+      --  Set/get the maximum socket receive buffer in bytes
+
+      Linger,          -- SO_LINGER
+      --  When enabled, a Close_Socket or Shutdown_Socket will wait until all
+      --  queued messages for the socket have been successfully sent or the
+      --  linger timeout has been reached.
+
+      Error,           -- SO_ERROR
+      --  Get and clear the pending socket error integer code
+
+      Send_Timeout,    -- SO_SNDTIMEO
+      --  Specify sending timeout until reporting an error
+
+      Receive_Timeout, -- SO_RCVTIMEO
+      --  Specify receiving timeout until reporting an error
+
+      Busy_Polling,    -- SO_BUSY_POLL
+      --  Sets the approximate time in microseconds to busy poll on a blocking
+      --  receive when there is no data.
+
+      -------------------------------
+      -- IP_Protocol_For_TCP_Level --
+      -------------------------------
+
+      No_Delay, -- TCP_NODELAY
+      --  Disable the Nagle algorithm. This means that output buffer content
+      --  is always sent as soon as possible, even if there is only a small
+      --  amount of data.
+
+      ------------------------------
+      -- IP_Protocol_For_IP_Level --
+      ------------------------------
+
+      Add_Membership_V4,   -- IP_ADD_MEMBERSHIP
+      --  Join a multicast group
+
+      Drop_Membership_V4,  -- IP_DROP_MEMBERSHIP
+      --  Leave a multicast group
+
+      Multicast_If_V4,     -- IP_MULTICAST_IF
+      --  Set/Get outgoing interface for sending multicast packets
+
+      Multicast_Loop_V4,   -- IP_MULTICAST_LOOP
+      --  This boolean option determines whether sent multicast packets should
+      --  be looped back to the local sockets.
+
+      Multicast_TTL,       -- IP_MULTICAST_TTL
+      --  Set/Get the time-to-live of sent multicast packets
+
+      Receive_Packet_Info, -- IP_PKTINFO
+      --  Receive low-level packet info as ancillary data
+
+      --------------------------------
+      -- IP_Protocol_For_IPv6_Level --
+      --------------------------------
+
+      Add_Membership_V6,   -- IPV6_ADD_MEMBERSHIP
+      --  Join IPv6 multicast group
+
+      Drop_Membership_V6,  -- IPV6_DROP_MEMBERSHIP
+      --  Leave IPv6 multicast group
+
+      Multicast_If_V6,     -- IPV6_MULTICAST_IF
+      --  Set/Get outgoing interface index for sending multicast packets
+
+      Multicast_Loop_V6,   -- IPV6_MULTICAST_LOOP
+      --  This boolean option determines whether sent multicast IPv6 packets
+      --  should be looped back to the local sockets.
+
+      IPv6_Only,           -- IPV6_V6ONLY
+      --  Restricted to IPv6 communications only
+
+      Multicast_Hops       -- IPV6_MULTICAST_HOPS
+      --  Set the multicast hop limit for the IPv6 socket
+     );
+
    subtype Specific_Option_Name is
      Option_Name range Keep_Alive .. Option_Name'Last;
 
@@ -1084,7 +1163,7 @@ package GNAT.Sockets is
 
    function Get_Socket_Option
      (Socket  : Socket_Type;
-      Level   : Level_Type := Socket_Level;
+      Level   : Level_Type;
       Name    : Option_Name;
       Optname : Interfaces.C.int := -1) return Option_Type;
    --  Get the options associated with a socket. Raises Socket_Error on error.
@@ -1199,7 +1278,7 @@ package GNAT.Sockets is
 
    procedure Set_Socket_Option
      (Socket : Socket_Type;
-      Level  : Level_Type := Socket_Level;
+      Level  : Level_Type;
       Option : Option_Type);
    --  Manipulate socket options. Raises Socket_Error on error