text: /* GIO - GLib Input, Output and Streaming Library
   *
   * Copyright (C) 2008 Christian Kellner, Samuel Cormier-Iijima
   * Copyright © 2009 Codethink Limited
   * Copyright © 2009 Red Hat, Inc
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General
   * Public License along with this library; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
   * Boston, MA 02111-1307, USA.
   *
   * Authors: Christian Kellner <gicmo@gnome.org>
   *          Samuel Cormier-Iijima <sciyoshi@gmail.com>
   *          Ryan Lortie <desrt@desrt.ca>
   *          Alexander Larsson <alexl@redhat.com>
   */
  
  #include "config.h"
  
  #include "gsocket.h"
  
  #include <errno.h>
  #include <signal.h>
  #include <string.h>
  #include <stdlib.h>
  
  #ifndef G_OS_WIN32
  # include <fcntl.h>
  # include <unistd.h>
  #endif
  
  #ifdef HAVE_SYS_UIO_H
  #include <sys/uio.h>
  #endif
  
  #include "gcancellable.h"
  #include "gioenumtypes.h"
  #include "ginetaddress.h"
  #include "ginitable.h"
  #include "gioerror.h"
  #include "gioenums.h"
  #include "gioerror.h"
  #include "gio-marshal.h"
  #include "gnetworkingprivate.h"
  #include "gsocketaddress.h"
  #include "gsocketcontrolmessage.h"
  #include "gcredentials.h"
  #include "glibintl.h"
  
  /**
   * SECTION:gsocket
   * @short_description: Low-level socket object
   * @include: gio/gio.h
   * @see_also: #GInitable
   *
   * A #GSocket is a low-level networking primitive. It is a more or less
   * direct mapping of the BSD socket API in a portable GObject based API.
   * It supports both the UNIX socket implementations and winsock2 on Windows.
   *
   * #GSocket is the platform independent base upon which the higher level
   * network primitives are based. Applications are not typically meant to
   * use it directly, but rather through classes like #GSocketClient,
   * #GSocketService and #GSocketConnection. However there may be cases where
   * direct use of #GSocket is useful.
   *
   * #GSocket implements the #GInitable interface, so if it is manually constructed
   * by e.g. g_object_new() you must call g_initable_init() and check the
   * results before using the object. This is done automatically in
   * g_socket_new() and g_socket_new_from_fd(), so these functions can return
   * %NULL.
   *
   * Sockets operate in two general modes, blocking or non-blocking. When
   * in blocking mode all operations block until the requested operation
   * is finished or there is an error. In non-blocking mode all calls that
   * would block return immediately with a %G_IO_ERROR_WOULD_BLOCK error.
   * To know when a call would successfully run you can call g_socket_condition_check(),
   * or g_socket_condition_wait(). You can also use g_socket_create_source() and
   * attach it to a #GMainContext to get callbacks when I/O is possible.
   * Note that all sockets are always set to non blocking mode in the system, and
   * blocking mode is emulated in GSocket.
   *
   * When working in non-blocking mode applications should always be able to
   * handle getting a %G_IO_ERROR_WOULD_BLOCK error even when some other
   * function said that I/O was possible. This can easily happen in case
   * of a race condition in the application, but it can also happen for other
   * reasons. For instance, on Windows a socket is always seen as writable
   * until a write returns %G_IO_ERROR_WOULD_BLOCK.
   *
   * #GSocket<!-- -->s can be either connection oriented or datagram based.
   * For connection oriented types you must first establish a connection by
   * either connecting to an address or accepting a connection from another
   * address. For connectionless socket types the target/source address is
   * specified or received in each I/O operation.
   *
   * All socket file descriptors are set to be close-on-exec.
   *
   * Note that creating a #GSocket causes the signal %SIGPIPE to be
   * ignored for the remainder of the program. If you are writing a
   * command-line utility that uses #GSocket, you may need to take into
   * account the fact that your program will not automatically be killed
   * if it tries to write to %stdout after it has been closed.
   *
   * Since: 2.22
   */
  
  static void     g_socket_initable_iface_init (GInitableIface  *iface);
  static gboolean g_socket_initable_init       (GInitable       *initable,
  					      GCancellable    *cancellable,
  					      GError         **error);
  
  G_DEFINE_TYPE_WITH_CODE (GSocket, g_socket, G_TYPE_OBJECT,
  			 G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,
  						g_socket_initable_iface_init));
  
  enum
  {
    PROP_0,
    PROP_FAMILY,
    PROP_TYPE,
    PROP_PROTOCOL,
    PROP_FD,
    PROP_BLOCKING,
    PROP_LISTEN_BACKLOG,
    PROP_KEEPALIVE,
    PROP_LOCAL_ADDRESS,
    PROP_REMOTE_ADDRESS,
    PROP_TIMEOUT
  };
  
  struct _GSocketPrivate
  {
    GSocketFamily   family;
    GSocketType     type;
    GSocketProtocol protocol;
    gint            fd;
    gint            listen_backlog;
    guint           timeout;
    GError         *construct_error;
    GSocketAddress *remote_address;
    guint           inited : 1;
    guint           blocking : 1;
    guint           keepalive : 1;
    guint           closed : 1;
    guint           connected : 1;
    guint           listening : 1;
    guint           timed_out : 1;
    guint           connect_pending : 1;
  #ifdef G_OS_WIN32
    WSAEVENT        event;
    int             current_events;
    int             current_errors;
    int             selected_events;
    GList          *requested_conditions; /* list of requested GIOCondition * */
  #endif
  };
  
  static int
  get_socket_errno (void)
  {
  #ifndef G_OS_WIN32
    return errno;
  #else
    return WSAGetLastError ();
  #endif
  }
  
  static GIOErrorEnum
  socket_io_error_from_errno (int err)
  {
  #ifndef G_OS_WIN32
    return g_io_error_from_errno (err);
  #else
    switch (err)
      {
      case WSAEADDRINUSE:
        return G_IO_ERROR_ADDRESS_IN_USE;
      case WSAEWOULDBLOCK:
        return G_IO_ERROR_WOULD_BLOCK;
      case WSAEACCES:
        return G_IO_ERROR_PERMISSION_DENIED;
      case WSA_INVALID_HANDLE:
      case WSA_INVALID_PARAMETER:
      case WSAEBADF:
      case WSAENOTSOCK:
        return G_IO_ERROR_INVALID_ARGUMENT;
      case WSAEPROTONOSUPPORT:
        return G_IO_ERROR_NOT_SUPPORTED;
      case WSAECANCELLED:
        return G_IO_ERROR_CANCELLED;
      case WSAESOCKTNOSUPPORT:
      case WSAEOPNOTSUPP:
      case WSAEPFNOSUPPORT:
      case WSAEAFNOSUPPORT:
        return G_IO_ERROR_NOT_SUPPORTED;
      default:
        return G_IO_ERROR_FAILED;
      }
  #endif
  }
  
  static const char *
  socket_strerror (int err)
  {
  #ifndef G_OS_WIN32
    return g_strerror (err);
  #else
    static GStaticPrivate last_msg = G_STATIC_PRIVATE_INIT;
    char *msg;
  
    msg = g_win32_error_message (err);
    g_static_private_set (&last_msg, msg, g_free);
  
    return msg;
  #endif
  }
  
  #ifdef G_OS_WIN32
  #define win32_unset_event_mask(_socket, _mask) _win32_unset_event_mask (_socket, _mask)
  static void
  _win32_unset_event_mask (GSocket *socket, int mask)
  {
    socket->priv->current_events &= ~mask;
    socket->priv->current_errors &= ~mask;
  }
  #else
  #define win32_unset_event_mask(_socket, _mask)
  #endif
  
  static void
  set_fd_nonblocking (int fd)
  {
  #ifndef G_OS_WIN32
    glong arg;
  #else
    gulong arg;
  #endif
  
  #ifndef G_OS_WIN32
    if ((arg = fcntl (fd, F_GETFL, NULL)) < 0)
      {
        g_warning ("Error getting socket status flags: %s", socket_strerror (errno));
        arg = 0;
      }
  
    arg = arg | O_NONBLOCK;
  
    if (fcntl (fd, F_SETFL, arg) < 0)
        g_warning ("Error setting socket status flags: %s", socket_strerror (errno));
  #else
    arg = TRUE;
  
    if (ioctlsocket (fd, FIONBIO, &arg) == SOCKET_ERROR)
      {
        int errsv = get_socket_errno ();
        g_warning ("Error setting socket status flags: %s", socket_strerror (errsv));
      }
  #endif
  }
  
  static gboolean
  check_socket (GSocket *socket,
  	      GError **error)
  {
    if (!socket->priv->inited)
      {
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_INITIALIZED,
                             _("Invalid socket, not initialized"));
        return FALSE;
      }
  
    if (socket->priv->construct_error)
      {
        g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_INITIALIZED,
  		   _("Invalid socket, initialization failed due to: %s"),
  		   socket->priv->construct_error->message);
        return FALSE;
      }
  
    if (socket->priv->closed)
      {
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
  			   _("Socket is already closed"));
        return FALSE;
      }
  
    if (socket->priv->timed_out)
      {
        socket->priv->timed_out = FALSE;
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_TIMED_OUT,
  			   _("Socket I/O timed out"));
        return FALSE;
      }
  
    return TRUE;
  }
  
  static void
  g_socket_details_from_fd (GSocket *socket)
  {
    struct sockaddr_storage address;
    gint fd;
    guint addrlen;
    guint optlen;
    int value;
    int errsv;
  #ifdef G_OS_WIN32
    /* See bug #611756 */
    BOOL bool_val = FALSE;
  #else
    int bool_val;
  #endif
  
    fd = socket->priv->fd;
    optlen = sizeof value;
    if (getsockopt (fd, SOL_SOCKET, SO_TYPE, (void *)&value, &optlen) != 0)
      {
        errsv = get_socket_errno ();
  
        switch (errsv)
  	{
  #ifdef ENOTSOCK
  	 case ENOTSOCK:
  #endif
  #ifdef WSAENOTSOCK
  	 case WSAENOTSOCK:
  #endif
  	 case EBADF:
  	  /* programmer error */
  	  g_error ("creating GSocket from fd %d: %s\n",
  		   fd, socket_strerror (errsv));
  	 default:
  	   break;
  	}
  
        goto err;
      }
  
    g_assert (optlen == sizeof value);
    switch (value)
      {
       case SOCK_STREAM:
        socket->priv->type = G_SOCKET_TYPE_STREAM;
        break;
  
       case SOCK_DGRAM:
        socket->priv->type = G_SOCKET_TYPE_DATAGRAM;
        break;
  
       case SOCK_SEQPACKET:
        socket->priv->type = G_SOCKET_TYPE_SEQPACKET;
        break;
  
       default:
        socket->priv->type = G_SOCKET_TYPE_INVALID;
        break;
      }
  
    addrlen = sizeof address;
    if (getsockname (fd, (struct sockaddr *) &address, &addrlen) != 0)
      {
        errsv = get_socket_errno ();
        goto err;
      }
  
    g_assert (G_STRUCT_OFFSET (struct sockaddr, sa_family) +
  	    sizeof address.ss_family <= addrlen);
    switch (address.ss_family)
      {
       case G_SOCKET_FAMILY_IPV4:
       case G_SOCKET_FAMILY_IPV6:
         socket->priv->family = address.ss_family;
         switch (socket->priv->type)
  	 {
  	 case G_SOCKET_TYPE_STREAM:
  	   socket->priv->protocol = G_SOCKET_PROTOCOL_TCP;
  	   break;
  
  	 case G_SOCKET_TYPE_DATAGRAM:
  	   socket->priv->protocol = G_SOCKET_PROTOCOL_UDP;
  	   break;
  
  	 case G_SOCKET_TYPE_SEQPACKET:
  	   socket->priv->protocol = G_SOCKET_PROTOCOL_SCTP;
  	   break;
  
  	 default:
  	   break;
  	 }
         break;
  
       case G_SOCKET_FAMILY_UNIX:
         socket->priv->family = G_SOCKET_FAMILY_UNIX;
         socket->priv->protocol = G_SOCKET_PROTOCOL_DEFAULT;
         break;
  
       default:
         socket->priv->family = G_SOCKET_FAMILY_INVALID;
         break;
      }
  
    if (socket->priv->family != G_SOCKET_FAMILY_INVALID)
      {
        addrlen = sizeof address;
        if (getpeername (fd, (struct sockaddr *) &address, &addrlen) >= 0)
  	socket->priv->connected = TRUE;
      }
  
    optlen = sizeof bool_val;
    if (getsockopt (fd, SOL_SOCKET, SO_KEEPALIVE,
  		  (void *)&bool_val, &optlen) == 0)
      {
  #ifndef G_OS_WIN32
        /* Experimentation indicates that the SO_KEEPALIVE value is
         * actually a char on Windows, even if documentation claims it
         * to be a BOOL which is a typedef for int. So this g_assert()
         * fails. See bug #611756.
         */
        g_assert (optlen == sizeof bool_val);
  #endif
        socket->priv->keepalive = !!bool_val;
      }
    else
      {
        /* Can't read, maybe not supported, assume FALSE */
        socket->priv->keepalive = FALSE;
      }
  
    return;
  
   err:
    g_set_error (&socket->priv->construct_error, G_IO_ERROR,
  	       socket_io_error_from_errno (errsv),
  	       _("creating GSocket from fd: %s"),
  	       socket_strerror (errsv));
  }
  
  static gint
  g_socket_create_socket (GSocketFamily   family,
  			GSocketType     type,
  			int             protocol,
  			GError        **error)
  {
    gint native_type;
    gint fd;
  
    switch (type)
      {
       case G_SOCKET_TYPE_STREAM:
        native_type = SOCK_STREAM;
        break;
  
       case G_SOCKET_TYPE_DATAGRAM:
        native_type = SOCK_DGRAM;
        break;
  
       case G_SOCKET_TYPE_SEQPACKET:
        native_type = SOCK_SEQPACKET;
        break;
  
       default:
        g_assert_not_reached ();
      }
  
    if (protocol == -1)
      {
        g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
  		   _("Unable to create socket: %s"), _("Unknown protocol was specified"));
        return -1;
      }
  
  #ifdef SOCK_CLOEXEC
    fd = socket (family, native_type | SOCK_CLOEXEC, protocol);
    /* It's possible that libc has SOCK_CLOEXEC but the kernel does not */
    if (fd < 0 && errno == EINVAL)
  #endif
      fd = socket (family, native_type, protocol);
  
    if (fd < 0)
      {
        int errsv = get_socket_errno ();
  
        g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("Unable to create socket: %s"), socket_strerror (errsv));
      }
  
  #ifndef G_OS_WIN32
    {
      int flags;
  
      /* We always want to set close-on-exec to protect users. If you
         need to so some weird inheritance to exec you can re-enable this
         using lower level hacks with g_socket_get_fd(). */
      flags = fcntl (fd, F_GETFD, 0);
      if (flags != -1 &&
  	(flags & FD_CLOEXEC) == 0)
        {
  	flags |= FD_CLOEXEC;
  	fcntl (fd, F_SETFD, flags);
        }
    }
  #endif
  
    return fd;
  }
  
  static void
  g_socket_constructed (GObject *object)
  {
    GSocket *socket = G_SOCKET (object);
  
    if (socket->priv->fd >= 0)
      /* create socket->priv info from the fd */
      g_socket_details_from_fd (socket);
  
    else
      /* create the fd from socket->priv info */
      socket->priv->fd = g_socket_create_socket (socket->priv->family,
  					       socket->priv->type,
  					       socket->priv->protocol,
  					       &socket->priv->construct_error);
  
    /* Always use native nonblocking sockets, as
       windows sets sockets to nonblocking automatically
       in certain operations. This way we make things work
       the same on all platforms */
    if (socket->priv->fd != -1)
      set_fd_nonblocking (socket->priv->fd);
  }
  
  static void
  g_socket_get_property (GObject    *object,
  		       guint       prop_id,
  		       GValue     *value,
  		       GParamSpec *pspec)
  {
    GSocket *socket = G_SOCKET (object);
    GSocketAddress *address;
  
    switch (prop_id)
      {
        case PROP_FAMILY:
  	g_value_set_enum (value, socket->priv->family);
  	break;
  
        case PROP_TYPE:
  	g_value_set_enum (value, socket->priv->type);
  	break;
  
        case PROP_PROTOCOL:
  	g_value_set_enum (value, socket->priv->protocol);
  	break;
  
        case PROP_FD:
  	g_value_set_int (value, socket->priv->fd);
  	break;
  
        case PROP_BLOCKING:
  	g_value_set_boolean (value, socket->priv->blocking);
  	break;
  
        case PROP_LISTEN_BACKLOG:
  	g_value_set_int (value, socket->priv->listen_backlog);
  	break;
  
        case PROP_KEEPALIVE:
  	g_value_set_boolean (value, socket->priv->keepalive);
  	break;
  
        case PROP_LOCAL_ADDRESS:
  	address = g_socket_get_local_address (socket, NULL);
  	g_value_take_object (value, address);
  	break;
  
        case PROP_REMOTE_ADDRESS:
  	address = g_socket_get_remote_address (socket, NULL);
  	g_value_take_object (value, address);
  	break;
  
        case PROP_TIMEOUT:
  	g_value_set_uint (value, socket->priv->timeout);
  	break;
  
        default:
  	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      }
  }
  
  static void
  g_socket_set_property (GObject      *object,
  		       guint         prop_id,
  		       const GValue *value,
  		       GParamSpec   *pspec)
  {
    GSocket *socket = G_SOCKET (object);
  
    switch (prop_id)
      {
        case PROP_FAMILY:
  	socket->priv->family = g_value_get_enum (value);
  	break;
  
        case PROP_TYPE:
  	socket->priv->type = g_value_get_enum (value);
  	break;
  
        case PROP_PROTOCOL:
  	socket->priv->protocol = g_value_get_enum (value);
  	break;
  
        case PROP_FD:
  	socket->priv->fd = g_value_get_int (value);
  	break;
  
        case PROP_BLOCKING:
  	g_socket_set_blocking (socket, g_value_get_boolean (value));
  	break;
  
        case PROP_LISTEN_BACKLOG:
  	g_socket_set_listen_backlog (socket, g_value_get_int (value));
  	break;
  
        case PROP_KEEPALIVE:
  	g_socket_set_keepalive (socket, g_value_get_boolean (value));
  	break;
  
        case PROP_TIMEOUT:
  	g_socket_set_timeout (socket, g_value_get_uint (value));
  	break;
  
        default:
  	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      }
  }
  
  static void
  g_socket_finalize (GObject *object)
  {
    GSocket *socket = G_SOCKET (object);
  
    g_clear_error (&socket->priv->construct_error);
  
    if (socket->priv->fd != -1 &&
        !socket->priv->closed)
      g_socket_close (socket, NULL);
  
    if (socket->priv->remote_address)
      g_object_unref (socket->priv->remote_address);
  
  #ifdef G_OS_WIN32
    if (socket->priv->event != WSA_INVALID_EVENT)
      {
        WSACloseEvent (socket->priv->event);
        socket->priv->event = WSA_INVALID_EVENT;
      }
  
    g_assert (socket->priv->requested_conditions == NULL);
  #endif
  
    if (G_OBJECT_CLASS (g_socket_parent_class)->finalize)
      (*G_OBJECT_CLASS (g_socket_parent_class)->finalize) (object);
  }
  
  static void
  g_socket_class_init (GSocketClass *klass)
  {
    GObjectClass *gobject_class G_GNUC_UNUSED = G_OBJECT_CLASS (klass);
    volatile GType type;
  
    /* Make sure winsock has been initialized */
    type = g_inet_address_get_type ();
  
  #ifdef SIGPIPE
    /* There is no portable, thread-safe way to avoid having the process
     * be killed by SIGPIPE when calling send() or sendmsg(), so we are
     * forced to simply ignore the signal process-wide.
     */
    signal (SIGPIPE, SIG_IGN);
  #endif
  
    g_type_class_add_private (klass, sizeof (GSocketPrivate));
  
    gobject_class->finalize = g_socket_finalize;
    gobject_class->constructed = g_socket_constructed;
    gobject_class->set_property = g_socket_set_property;
    gobject_class->get_property = g_socket_get_property;
  
    g_object_class_install_property (gobject_class, PROP_FAMILY,
  				   g_param_spec_enum ("family",
  						      P_("Socket family"),
  						      P_("The sockets address family"),
  						      G_TYPE_SOCKET_FAMILY,
  						      G_SOCKET_FAMILY_INVALID,
  						      G_PARAM_CONSTRUCT_ONLY |
                                                        G_PARAM_READWRITE |
                                                        G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_TYPE,
  				   g_param_spec_enum ("type",
  						      P_("Socket type"),
  						      P_("The sockets type"),
  						      G_TYPE_SOCKET_TYPE,
  						      G_SOCKET_TYPE_STREAM,
  						      G_PARAM_CONSTRUCT_ONLY |
                                                        G_PARAM_READWRITE |
                                                        G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_PROTOCOL,
  				   g_param_spec_enum ("protocol",
  						      P_("Socket protocol"),
  						      P_("The id of the protocol to use, or -1 for unknown"),
  						      G_TYPE_SOCKET_PROTOCOL,
  						      G_SOCKET_PROTOCOL_UNKNOWN,
  						      G_PARAM_CONSTRUCT_ONLY |
                                                        G_PARAM_READWRITE |
                                                        G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_FD,
  				   g_param_spec_int ("fd",
  						     P_("File descriptor"),
  						     P_("The sockets file descriptor"),
  						     G_MININT,
  						     G_MAXINT,
  						     -1,
  						     G_PARAM_CONSTRUCT_ONLY |
                                                       G_PARAM_READWRITE |
                                                       G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_BLOCKING,
  				   g_param_spec_boolean ("blocking",
  							 P_("blocking"),
  							 P_("Whether or not I/O on this socket is blocking"),
  							 TRUE,
  							 G_PARAM_READWRITE |
                                                           G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_LISTEN_BACKLOG,
  				   g_param_spec_int ("listen-backlog",
  						     P_("Listen backlog"),
  						     P_("Outstanding connections in the listen queue"),
  						     0,
  						     SOMAXCONN,
  						     10,
  						     G_PARAM_READWRITE |
                                                       G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_KEEPALIVE,
  				   g_param_spec_boolean ("keepalive",
  							 P_("Keep connection alive"),
  							 P_("Keep connection alive by sending periodic pings"),
  							 FALSE,
  							 G_PARAM_READWRITE |
                                                           G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_LOCAL_ADDRESS,
  				   g_param_spec_object ("local-address",
  							P_("Local address"),
  							P_("The local address the socket is bound to"),
  							G_TYPE_SOCKET_ADDRESS,
  							G_PARAM_READABLE |
                                                          G_PARAM_STATIC_STRINGS));
  
    g_object_class_install_property (gobject_class, PROP_REMOTE_ADDRESS,
  				   g_param_spec_object ("remote-address",
  							P_("Remote address"),
  							P_("The remote address the socket is connected to"),
  							G_TYPE_SOCKET_ADDRESS,
  							G_PARAM_READABLE |
                                                          G_PARAM_STATIC_STRINGS));
  
    /**
     * GSocket:timeout:
     *
     * The timeout in seconds on socket I/O
     *
     * Since: 2.26
     */
    g_object_class_install_property (gobject_class, PROP_TIMEOUT,
  				   g_param_spec_uint ("timeout",
  						      P_("Timeout"),
  						      P_("The timeout in seconds on socket I/O"),
  						      0,
  						      G_MAXUINT,
  						      0,
  						      G_PARAM_READWRITE |
  						      G_PARAM_STATIC_STRINGS));
  }
  
  static void
  g_socket_initable_iface_init (GInitableIface *iface)
  {
    iface->init = g_socket_initable_init;
  }
  
  static void
  g_socket_init (GSocket *socket)
  {
    socket->priv = G_TYPE_INSTANCE_GET_PRIVATE (socket, G_TYPE_SOCKET, GSocketPrivate);
  
    socket->priv->fd = -1;
    socket->priv->blocking = TRUE;
    socket->priv->listen_backlog = 10;
    socket->priv->construct_error = NULL;
  #ifdef G_OS_WIN32
    socket->priv->event = WSA_INVALID_EVENT;
  #endif
  }
  
  static gboolean
  g_socket_initable_init (GInitable *initable,
  			GCancellable *cancellable,
  			GError  **error)
  {
    GSocket  *socket;
  
    g_return_val_if_fail (G_IS_SOCKET (initable), FALSE);
  
    socket = G_SOCKET (initable);
  
    if (cancellable != NULL)
      {
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
                             _("Cancellable initialization not supported"));
        return FALSE;
      }
  
    socket->priv->inited = TRUE;
  
    if (socket->priv->construct_error)
      {
        if (error)
  	*error = g_error_copy (socket->priv->construct_error);
        return FALSE;
      }
  
  
    return TRUE;
  }
  
  /**
   * g_socket_new:
   * @family: the socket family to use, e.g. %G_SOCKET_FAMILY_IPV4.
   * @type: the socket type to use.
   * @protocol: the id of the protocol to use, or 0 for default.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Creates a new #GSocket with the defined family, type and protocol.
   * If @protocol is 0 (%G_SOCKET_PROTOCOL_DEFAULT) the default protocol type
   * for the family and type is used.
   *
   * The @protocol is a family and type specific int that specifies what
   * kind of protocol to use. #GSocketProtocol lists several common ones.
   * Many families only support one protocol, and use 0 for this, others
   * support several and using 0 means to use the default protocol for
   * the family and type.
   *
   * The protocol id is passed directly to the operating
   * system, so you can use protocols not listed in #GSocketProtocol if you
   * know the protocol number used for it.
   *
   * Returns: a #GSocket or %NULL on error.
   *     Free the returned object with g_object_unref().
   *
   * Since: 2.22
   */
  GSocket *
  g_socket_new (GSocketFamily     family,
  	      GSocketType       type,
  	      GSocketProtocol   protocol,
  	      GError          **error)
  {
    return G_SOCKET (g_initable_new (G_TYPE_SOCKET,
  				   NULL, error,
  				   "family", family,
  				   "type", type,
  				   "protocol", protocol,
  				   NULL));
  }
  
  /**
   * g_socket_new_from_fd:
   * @fd: a native socket file descriptor.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Creates a new #GSocket from a native file descriptor
   * or winsock SOCKET handle.
   *
   * This reads all the settings from the file descriptor so that
   * all properties should work. Note that the file descriptor
   * will be set to non-blocking mode, independent on the blocking
   * mode of the #GSocket.
   *
   * Returns: a #GSocket or %NULL on error.
   *     Free the returned object with g_object_unref().
   *
   * Since: 2.22
   */
  GSocket *
  g_socket_new_from_fd (gint     fd,
  		      GError **error)
  {
    return G_SOCKET (g_initable_new (G_TYPE_SOCKET,
  				   NULL, error,
  				   "fd", fd,
  				   NULL));
  }
  
  /**
   * g_socket_set_blocking:
   * @socket: a #GSocket.
   * @blocking: Whether to use blocking I/O or not.
   *
   * Sets the blocking mode of the socket. In blocking mode
   * all operations block until they succeed or there is an error. In
   * non-blocking mode all functions return results immediately or
   * with a %G_IO_ERROR_WOULD_BLOCK error.
   *
   * All sockets are created in blocking mode. However, note that the
   * platform level socket is always non-blocking, and blocking mode
   * is a GSocket level feature.
   *
   * Since: 2.22
   */
  void
  g_socket_set_blocking (GSocket  *socket,
  		       gboolean  blocking)
  {
    g_return_if_fail (G_IS_SOCKET (socket));
  
    blocking = !!blocking;
  
    if (socket->priv->blocking == blocking)
      return;
  
    socket->priv->blocking = blocking;
    g_object_notify (G_OBJECT (socket), "blocking");
  }
  
  /**
   * g_socket_get_blocking:
   * @socket: a #GSocket.
   *
   * Gets the blocking mode of the socket. For details on blocking I/O,
   * see g_socket_set_blocking().
   *
   * Returns: %TRUE if blocking I/O is used, %FALSE otherwise.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_get_blocking (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
  
    return socket->priv->blocking;
  }
  
  /**
   * g_socket_set_keepalive:
   * @socket: a #GSocket.
   * @keepalive: Value for the keepalive flag
   *
   * Sets or unsets the %SO_KEEPALIVE flag on the underlying socket. When
   * this flag is set on a socket, the system will attempt to verify that the
   * remote socket endpoint is still present if a sufficiently long period of
   * time passes with no data being exchanged. If the system is unable to
   * verify the presence of the remote endpoint, it will automatically close
   * the connection.
   *
   * This option is only functional on certain kinds of sockets. (Notably,
   * %G_SOCKET_PROTOCOL_TCP sockets.)
   *
   * The exact time between pings is system- and protocol-dependent, but will
   * normally be at least two hours. Most commonly, you would set this flag
   * on a server socket if you want to allow clients to remain idle for long
   * periods of time, but also want to ensure that connections are eventually
   * garbage-collected if clients crash or become unreachable.
   *
   * Since: 2.22
   */
  void
  g_socket_set_keepalive (GSocket  *socket,
  			gboolean  keepalive)
  {
    int value;
  
    g_return_if_fail (G_IS_SOCKET (socket));
  
    keepalive = !!keepalive;
    if (socket->priv->keepalive == keepalive)
      return;
  
    value = (gint) keepalive;
    if (setsockopt (socket->priv->fd, SOL_SOCKET, SO_KEEPALIVE,
  		  (gpointer) &value, sizeof (value)) < 0)
      {
        int errsv = get_socket_errno ();
        g_warning ("error setting keepalive: %s", socket_strerror (errsv));
        return;
      }
  
    socket->priv->keepalive = keepalive;
    g_object_notify (G_OBJECT (socket), "keepalive");
  }
  
  /**
   * g_socket_get_keepalive:
   * @socket: a #GSocket.
   *
   * Gets the keepalive mode of the socket. For details on this,
   * see g_socket_set_keepalive().
   *
   * Returns: %TRUE if keepalive is active, %FALSE otherwise.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_get_keepalive (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
  
    return socket->priv->keepalive;
  }
  
  /**
   * g_socket_get_listen_backlog:
   * @socket: a #GSocket.
   *
   * Gets the listen backlog setting of the socket. For details on this,
   * see g_socket_set_listen_backlog().
   *
   * Returns: the maximum number of pending connections.
   *
   * Since: 2.22
   */
  gint
  g_socket_get_listen_backlog  (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), 0);
  
    return socket->priv->listen_backlog;
  }
  
  /**
   * g_socket_set_listen_backlog:
   * @socket: a #GSocket.
   * @backlog: the maximum number of pending connections.
   *
   * Sets the maximum number of outstanding connections allowed
   * when listening on this socket. If more clients than this are
   * connecting to the socket and the application is not handling them
   * on time then the new connections will be refused.
   *
   * Note that this must be called before g_socket_listen() and has no
   * effect if called after that.
   *
   * Since: 2.22
   */
  void
  g_socket_set_listen_backlog (GSocket *socket,
  			     gint     backlog)
  {
    g_return_if_fail (G_IS_SOCKET (socket));
    g_return_if_fail (!socket->priv->listening);
  
    if (backlog != socket->priv->listen_backlog)
      {
        socket->priv->listen_backlog = backlog;
        g_object_notify (G_OBJECT (socket), "listen-backlog");
      }
  }
  
  /**
   * g_socket_get_timeout:
   * @socket: a #GSocket.
   *
   * Gets the timeout setting of the socket. For details on this, see
   * g_socket_set_timeout().
   *
   * Returns: the timeout in seconds
   *
   * Since: 2.26
   */
  guint
  g_socket_get_timeout (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), 0);
  
    return socket->priv->timeout;
  }
  
  /**
   * g_socket_set_timeout:
   * @socket: a #GSocket.
   * @timeout: the timeout for @socket, in seconds, or 0 for none
   *
   * Sets the time in seconds after which I/O operations on @socket will
   * time out if they have not yet completed.
   *
   * On a blocking socket, this means that any blocking #GSocket
   * operation will time out after @timeout seconds of inactivity,
   * returning %G_IO_ERROR_TIMED_OUT.
   *
   * On a non-blocking socket, calls to g_socket_condition_wait() will
   * also fail with %G_IO_ERROR_TIMED_OUT after the given time. Sources
   * created with g_socket_create_source() will trigger after
   * @timeout seconds of inactivity, with the requested condition
   * set, at which point calling g_socket_receive(), g_socket_send(),
   * g_socket_check_connect_result(), etc, will fail with
   * %G_IO_ERROR_TIMED_OUT.
   *
   * If @timeout is 0 (the default), operations will never time out
   * on their own.
   *
   * Note that if an I/O operation is interrupted by a signal, this may
   * cause the timeout to be reset.
   *
   * Since: 2.26
   */
  void
  g_socket_set_timeout (GSocket *socket,
  		      guint    timeout)
  {
    g_return_if_fail (G_IS_SOCKET (socket));
  
    if (timeout != socket->priv->timeout)
      {
        socket->priv->timeout = timeout;
        g_object_notify (G_OBJECT (socket), "timeout");
      }
  }
  
  /**
   * g_socket_get_family:
   * @socket: a #GSocket.
   *
   * Gets the socket family of the socket.
   *
   * Returns: a #GSocketFamily
   *
   * Since: 2.22
   */
  GSocketFamily
  g_socket_get_family (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), G_SOCKET_FAMILY_INVALID);
  
    return socket->priv->family;
  }
  
  /**
   * g_socket_get_socket_type:
   * @socket: a #GSocket.
   *
   * Gets the socket type of the socket.
   *
   * Returns: a #GSocketType
   *
   * Since: 2.22
   */
  GSocketType
  g_socket_get_socket_type (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), G_SOCKET_TYPE_INVALID);
  
    return socket->priv->type;
  }
  
  /**
   * g_socket_get_protocol:
   * @socket: a #GSocket.
   *
   * Gets the socket protocol id the socket was created with.
   * In case the protocol is unknown, -1 is returned.
   *
   * Returns: a protocol id, or -1 if unknown
   *
   * Since: 2.22
   */
  GSocketProtocol
  g_socket_get_protocol (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), -1);
  
    return socket->priv->protocol;
  }
  
  /**
   * g_socket_get_fd:
   * @socket: a #GSocket.
   *
   * Returns the underlying OS socket object. On unix this
   * is a socket file descriptor, and on windows this is
   * a Winsock2 SOCKET handle. This may be useful for
   * doing platform specific or otherwise unusual operations
   * on the socket.
   *
   * Returns: the file descriptor of the socket.
   *
   * Since: 2.22
   */
  int
  g_socket_get_fd (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), -1);
  
    return socket->priv->fd;
  }
  
  /**
   * g_socket_get_local_address:
   * @socket: a #GSocket.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Try to get the local address of a bound socket. This is only
   * useful if the socket has been bound to a local address,
   * either explicitly or implicitly when connecting.
   *
   * Returns: (transfer full): a #GSocketAddress or %NULL on error.
   *     Free the returned object with g_object_unref().
   *
   * Since: 2.22
   */
  GSocketAddress *
  g_socket_get_local_address (GSocket  *socket,
  			    GError  **error)
  {
    struct sockaddr_storage buffer;
    guint32 len = sizeof (buffer);
  
    g_return_val_if_fail (G_IS_SOCKET (socket), NULL);
  
    if (getsockname (socket->priv->fd, (struct sockaddr *) &buffer, &len) < 0)
      {
        int errsv = get_socket_errno ();
        g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("could not get local address: %s"), socket_strerror (errsv));
        return NULL;
      }
  
    return g_socket_address_new_from_native (&buffer, len);
  }
  
  /**
   * g_socket_get_remote_address:
   * @socket: a #GSocket.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Try to get the remove address of a connected socket. This is only
   * useful for connection oriented sockets that have been connected.
   *
   * Returns: (transfer full): a #GSocketAddress or %NULL on error.
   *     Free the returned object with g_object_unref().
   *
   * Since: 2.22
   */
  GSocketAddress *
  g_socket_get_remote_address (GSocket  *socket,
  			     GError  **error)
  {
    struct sockaddr_storage buffer;
    guint32 len = sizeof (buffer);
  
    g_return_val_if_fail (G_IS_SOCKET (socket), NULL);
  
    if (socket->priv->connect_pending)
      {
        if (!g_socket_check_connect_result (socket, error))
          return NULL;
        else
          socket->priv->connect_pending = FALSE;
      }
  
    if (!socket->priv->remote_address)
      {
        if (getpeername (socket->priv->fd, (struct sockaddr *) &buffer, &len) < 0)
  	{
  	  int errsv = get_socket_errno ();
  	  g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		       _("could not get remote address: %s"), socket_strerror (errsv));
  	  return NULL;
  	}
  
        socket->priv->remote_address = g_socket_address_new_from_native (&buffer, len);
      }
  
    return g_object_ref (socket->priv->remote_address);
  }
  
  /**
   * g_socket_is_connected:
   * @socket: a #GSocket.
   *
   * Check whether the socket is connected. This is only useful for
   * connection-oriented sockets.
   *
   * Returns: %TRUE if socket is connected, %FALSE otherwise.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_is_connected (GSocket *socket)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
  
    return socket->priv->connected;
  }
  
  /**
   * g_socket_listen:
   * @socket: a #GSocket.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Marks the socket as a server socket, i.e. a socket that is used
   * to accept incoming requests using g_socket_accept().
   *
   * Before calling this the socket must be bound to a local address using
   * g_socket_bind().
   *
   * To set the maximum amount of outstanding clients, use
   * g_socket_set_listen_backlog().
   *
   * Returns: %TRUE on success, %FALSE on error.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_listen (GSocket  *socket,
  		 GError  **error)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket), FALSE);
  
    if (!check_socket (socket, error))
      return FALSE;
  
    if (listen (socket->priv->fd, socket->priv->listen_backlog) < 0)
      {
        int errsv = get_socket_errno ();
  
        g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("could not listen: %s"), socket_strerror (errsv));
        return FALSE;
      }
  
    socket->priv->listening = TRUE;
  
    return TRUE;
  }
  
  /**
   * g_socket_bind:
   * @socket: a #GSocket.
   * @address: a #GSocketAddress specifying the local address.
   * @allow_reuse: whether to allow reusing this address
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * When a socket is created it is attached to an address family, but it
   * doesn't have an address in this family. g_socket_bind() assigns the
   * address (sometimes called name) of the socket.
   *
   * It is generally required to bind to a local address before you can
   * receive connections. (See g_socket_listen() and g_socket_accept() ).
   * In certain situations, you may also want to bind a socket that will be
   * used to initiate connections, though this is not normally required.
   *
   * @allow_reuse should be %TRUE for server sockets (sockets that you will
   * eventually call g_socket_accept() on), and %FALSE for client sockets.
   * (Specifically, if it is %TRUE, then g_socket_bind() will set the
   * %SO_REUSEADDR flag on the socket, allowing it to bind @address even if
   * that address was previously used by another socket that has not yet been
   * fully cleaned-up by the kernel. Failing to set this flag on a server
   * socket may cause the bind call to return %G_IO_ERROR_ADDRESS_IN_USE if
   * the server program is stopped and then immediately restarted.)
   *
   * Returns: %TRUE on success, %FALSE on error.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_bind (GSocket         *socket,
  	       GSocketAddress  *address,
  	       gboolean         reuse_address,
  	       GError         **error)
  {
    struct sockaddr_storage addr;
  
    g_return_val_if_fail (G_IS_SOCKET (socket) && G_IS_SOCKET_ADDRESS (address), FALSE);
  
    if (!check_socket (socket, error))
      return FALSE;
  
    /* SO_REUSEADDR on windows means something else and is not what we want.
       It always allows the unix variant of SO_REUSEADDR anyway */
  #ifndef G_OS_WIN32
    {
      int value;
  
      value = (int) !!reuse_address;
      /* Ignore errors here, the only likely error is "not supported", and
         this is a "best effort" thing mainly */
      setsockopt (socket->priv->fd, SOL_SOCKET, SO_REUSEADDR,
  		(gpointer) &value, sizeof (value));
    }
  #endif
  
    if (!g_socket_address_to_native (address, &addr, sizeof addr, error))
      return FALSE;
  
    if (bind (socket->priv->fd, (struct sockaddr *) &addr,
  	    g_socket_address_get_native_size (address)) < 0)
      {
        int errsv = get_socket_errno ();
        g_set_error (error,
  		   G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("Error binding to address: %s"), socket_strerror (errsv));
        return FALSE;
      }
  
    return TRUE;
  }
  
  /**
   * g_socket_speaks_ipv4:
   * @socket: a #GSocket
   *
   * Checks if a socket is capable of speaking IPv4.
   *
   * IPv4 sockets are capable of speaking IPv4.  On some operating systems
   * and under some combinations of circumstances IPv6 sockets are also
   * capable of speaking IPv4.  See RFC 3493 section 3.7 for more
   * information.
   *
   * No other types of sockets are currently considered as being capable
   * of speaking IPv4.
   *
   * Returns: %TRUE if this socket can be used with IPv4.
   *
   * Since: 2.22
   **/
  gboolean
  g_socket_speaks_ipv4 (GSocket *socket)
  {
    switch (socket->priv->family)
      {
      case G_SOCKET_FAMILY_IPV4:
        return TRUE;
  
      case G_SOCKET_FAMILY_IPV6:
  #if defined (IPPROTO_IPV6) && defined (IPV6_V6ONLY)
        {
          guint sizeof_int = sizeof (int);
          gint v6_only;
  
          if (getsockopt (socket->priv->fd,
                          IPPROTO_IPV6, IPV6_V6ONLY,
                          &v6_only, &sizeof_int) != 0)
            return FALSE;
  
          return !v6_only;
        }
  #else
        return FALSE;
  #endif
  
      default:
        return FALSE;
      }
  }
  
  /**
   * g_socket_accept:
   * @socket: a #GSocket.
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Accept incoming connections on a connection-based socket. This removes
   * the first outstanding connection request from the listening socket and
   * creates a #GSocket object for it.
   *
   * The @socket must be bound to a local address with g_socket_bind() and
   * must be listening for incoming connections (g_socket_listen()).
   *
   * If there are no outstanding connections then the operation will block
   * or return %G_IO_ERROR_WOULD_BLOCK if non-blocking I/O is enabled.
   * To be notified of an incoming connection, wait for the %G_IO_IN condition.
   *
   * Returns: (transfer full): a new #GSocket, or %NULL on error.
   *     Free the returned object with g_object_unref().
   *
   * Since: 2.22
   */
  GSocket *
  g_socket_accept (GSocket       *socket,
  		 GCancellable  *cancellable,
  		 GError       **error)
  {
    GSocket *new_socket;
    gint ret;
  
    g_return_val_if_fail (G_IS_SOCKET (socket), NULL);
  
    if (!check_socket (socket, error))
      return NULL;
  
    while (TRUE)
      {
        if (socket->priv->blocking &&
  	  !g_socket_condition_wait (socket,
  				    G_IO_IN, cancellable, error))
  	return NULL;
  
        if ((ret = accept (socket->priv->fd, NULL, 0)) < 0)
  	{
  	  int errsv = get_socket_errno ();
  
  	  win32_unset_event_mask (socket, FD_ACCEPT);
  
  	  if (errsv == EINTR)
  	    continue;
  
  	  if (socket->priv->blocking)
  	    {
  #ifdef WSAEWOULDBLOCK
  	      if (errsv == WSAEWOULDBLOCK)
  		continue;
  #else
  	      if (errsv == EWOULDBLOCK ||
  		  errsv == EAGAIN)
  		continue;
  #endif
  	    }
  
  	  g_set_error (error, G_IO_ERROR,
  		       socket_io_error_from_errno (errsv),
  		       _("Error accepting connection: %s"), socket_strerror (errsv));
  	  return NULL;
  	}
        break;
      }
  
    win32_unset_event_mask (socket, FD_ACCEPT);
  
  #ifdef G_OS_WIN32
    {
      /* The socket inherits the accepting sockets event mask and even object,
         we need to remove that */
      WSAEventSelect (ret, NULL, 0);
    }
  #else
    {
      int flags;
  
      /* We always want to set close-on-exec to protect users. If you
         need to so some weird inheritance to exec you can re-enable this
         using lower level hacks with g_socket_get_fd(). */
      flags = fcntl (ret, F_GETFD, 0);
      if (flags != -1 &&
  	(flags & FD_CLOEXEC) == 0)
        {
  	flags |= FD_CLOEXEC;
  	fcntl (ret, F_SETFD, flags);
        }
    }
  #endif
  
    new_socket = g_socket_new_from_fd (ret, error);
    if (new_socket == NULL)
      {
  #ifdef G_OS_WIN32
        closesocket (ret);
  #else
        close (ret);
  #endif
      }
    else
      new_socket->priv->protocol = socket->priv->protocol;
  
    return new_socket;
  }
  
  /**
   * g_socket_connect:
   * @socket: a #GSocket.
   * @address: a #GSocketAddress specifying the remote address.
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Connect the socket to the specified remote address.
   *
   * For connection oriented socket this generally means we attempt to make
   * a connection to the @address. For a connection-less socket it sets
   * the default address for g_socket_send() and discards all incoming datagrams
   * from other sources.
   *
   * Generally connection oriented sockets can only connect once, but
   * connection-less sockets can connect multiple times to change the
   * default address.
   *
   * If the connect call needs to do network I/O it will block, unless
   * non-blocking I/O is enabled. Then %G_IO_ERROR_PENDING is returned
   * and the user can be notified of the connection finishing by waiting
   * for the G_IO_OUT condition. The result of the connection can then be
   * checked with g_socket_check_connect_result().
   *
   * Returns: %TRUE if connected, %FALSE on error.
   *
   * Since: 2.22
   */
  gboolean
  g_socket_connect (GSocket         *socket,
  		  GSocketAddress  *address,
  		  GCancellable    *cancellable,
  		  GError         **error)
  {
    struct sockaddr_storage buffer;
  
    g_return_val_if_fail (G_IS_SOCKET (socket) && G_IS_SOCKET_ADDRESS (address), FALSE);
  
    if (!check_socket (socket, error))
      return FALSE;
  
    if (!g_socket_address_to_native (address, &buffer, sizeof buffer, error))
      return FALSE;
  
    if (socket->priv->remote_address)
      g_object_unref (socket->priv->remote_address);
    socket->priv->remote_address = g_object_ref (address);
  
    while (1)
      {
        if (connect (socket->priv->fd, (struct sockaddr *) &buffer,
  		   g_socket_address_get_native_size (address)) < 0)
  	{
  	  int errsv = get_socket_errno ();
  
  	  if (errsv == EINTR)
  	    continue;
  
  #ifndef G_OS_WIN32
  	  if (errsv == EINPROGRESS)
  #else
  	  if (errsv == WSAEWOULDBLOCK)
  #endif
  	    {
  	      if (socket->priv->blocking)
  		{
  		  if (g_socket_condition_wait (socket, G_IO_OUT, cancellable, error))
  		    {
  		      if (g_socket_check_connect_result (socket, error))
  			break;
  		    }
  		  g_prefix_error (error, _("Error connecting: "));
  		}
  	      else
                  {
                    g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
                                         _("Connection in progress"));
                    socket->priv->connect_pending = TRUE;
                  }
  	    }
  	  else
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Error connecting: %s"), socket_strerror (errsv));
  
  	  return FALSE;
  	}
        break;
      }
  
    win32_unset_event_mask (socket, FD_CONNECT);
  
    socket->priv->connected = TRUE;
  
    return TRUE;
  }
  
  /**
   * g_socket_check_connect_result:
   * @socket: a #GSocket
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Checks and resets the pending connect error for the socket.
   * This is used to check for errors when g_socket_connect() is
   * used in non-blocking mode.
   *
   * Returns: %TRUE if no error, %FALSE otherwise, setting @error to the error
   *
   * Since: 2.22
   */
  gboolean
  g_socket_check_connect_result (GSocket  *socket,
  			       GError  **error)
  {
    guint optlen;
    int value;
  
    if (!check_socket (socket, error))
      return FALSE;
  
    optlen = sizeof (value);
    if (getsockopt (socket->priv->fd, SOL_SOCKET, SO_ERROR, (void *)&value, &optlen) != 0)
      {
        int errsv = get_socket_errno ();
  
        g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("Unable to get pending error: %s"), socket_strerror (errsv));
        return FALSE;
      }
  
    if (value != 0)
      {
        g_set_error_literal (error, G_IO_ERROR, socket_io_error_from_errno (value),
                             socket_strerror (value));
        if (socket->priv->remote_address)
          {
            g_object_unref (socket->priv->remote_address);
            socket->priv->remote_address = NULL;
          }
        return FALSE;
      }
    return TRUE;
  }
  
  /**
   * g_socket_receive:
   * @socket: a #GSocket
   * @buffer: a buffer to read data into (which should be at least @size
   *     bytes long).
   * @size: the number of bytes you want to read from the socket
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Receive data (up to @size bytes) from a socket. This is mainly used by
   * connection-oriented sockets; it is identical to g_socket_receive_from()
   * with @address set to %NULL.
   *
   * For %G_SOCKET_TYPE_DATAGRAM and %G_SOCKET_TYPE_SEQPACKET sockets,
   * g_socket_receive() will always read either 0 or 1 complete messages from
   * the socket. If the received message is too large to fit in @buffer, then
   * the data beyond @size bytes will be discarded, without any explicit
   * indication that this has occurred.
   *
   * For %G_SOCKET_TYPE_STREAM sockets, g_socket_receive() can return any
   * number of bytes, up to @size. If more than @size bytes have been
   * received, the additional data will be returned in future calls to
   * g_socket_receive().
   *
   * If the socket is in blocking mode the call will block until there is
   * some data to receive or there is an error. If there is no data available
   * and the socket is in non-blocking mode, a %G_IO_ERROR_WOULD_BLOCK error
   * will be returned. To be notified when data is available, wait for the
   * %G_IO_IN condition.
   *
   * On error -1 is returned and @error is set accordingly.
   *
   * Returns: Number of bytes read, or -1 on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_receive (GSocket       *socket,
  		  gchar         *buffer,
  		  gsize          size,
  		  GCancellable  *cancellable,
  		  GError       **error)
  {
    return g_socket_receive_with_blocking (socket, buffer, size,
  					 socket->priv->blocking,
  					 cancellable, error);
  }
  
  /**
   * g_socket_receive_with_blocking:
   * @socket: a #GSocket
   * @buffer: a buffer to read data into (which should be at least @size
   *     bytes long).
   * @size: the number of bytes you want to read from the socket
   * @blocking: whether to do blocking or non-blocking I/O
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * This behaves exactly the same as g_socket_receive(), except that
   * the choice of blocking or non-blocking behavior is determined by
   * the @blocking argument rather than by @socket's properties.
   *
   * Returns: Number of bytes read, or -1 on error
   *
   * Since: 2.26
   */
  gssize
  g_socket_receive_with_blocking (GSocket       *socket,
  				gchar         *buffer,
  				gsize          size,
  				gboolean       blocking,
  				GCancellable  *cancellable,
  				GError       **error)
  {
    gssize ret;
  
    g_return_val_if_fail (G_IS_SOCKET (socket) && buffer != NULL, FALSE);
  
    if (!check_socket (socket, error))
      return -1;
  
    if (g_cancellable_set_error_if_cancelled (cancellable, error))
      return -1;
  
    while (1)
      {
        if (blocking &&
  	  !g_socket_condition_wait (socket,
  				    G_IO_IN, cancellable, error))
  	return -1;
  
        if ((ret = recv (socket->priv->fd, buffer, size, 0)) < 0)
  	{
  	  int errsv = get_socket_errno ();
  
  	  if (errsv == EINTR)
  	    continue;
  
  	  if (blocking)
  	    {
  #ifdef WSAEWOULDBLOCK
  	      if (errsv == WSAEWOULDBLOCK)
  		continue;
  #else
  	      if (errsv == EWOULDBLOCK ||
  		  errsv == EAGAIN)
  		continue;
  #endif
  	    }
  
  	  win32_unset_event_mask (socket, FD_READ);
  
  	  g_set_error (error, G_IO_ERROR,
  		       socket_io_error_from_errno (errsv),
  		       _("Error receiving data: %s"), socket_strerror (errsv));
  	  return -1;
  	}
  
        win32_unset_event_mask (socket, FD_READ);
  
        break;
      }
  
    return ret;
  }
  
  /**
   * g_socket_receive_from:
   * @socket: a #GSocket
   * @address: a pointer to a #GSocketAddress pointer, or %NULL
   * @buffer: a buffer to read data into (which should be at least @size
   *     bytes long).
   * @size: the number of bytes you want to read from the socket
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Receive data (up to @size bytes) from a socket.
   *
   * If @address is non-%NULL then @address will be set equal to the
   * source address of the received packet.
   * @address is owned by the caller.
   *
   * See g_socket_receive() for additional information.
   *
   * Returns: Number of bytes read, or -1 on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_receive_from (GSocket         *socket,
  		       GSocketAddress **address,
  		       gchar           *buffer,
  		       gsize            size,
  		       GCancellable    *cancellable,
  		       GError         **error)
  {
    GInputVector v;
  
    v.buffer = buffer;
    v.size = size;
  
    return g_socket_receive_message (socket,
  				   address,
  				   &v, 1,
  				   NULL, 0, NULL,
  				   cancellable,
  				   error);
  }
  
  /* Although we ignore SIGPIPE, gdb will still stop if the app receives
   * one, which can be confusing and annoying. So if possible, we want
   * to suppress the signal entirely.
   */
  #ifdef MSG_NOSIGNAL
  #define G_SOCKET_DEFAULT_SEND_FLAGS MSG_NOSIGNAL
  #else
  #define G_SOCKET_DEFAULT_SEND_FLAGS 0
  #endif
  
  /**
   * g_socket_send:
   * @socket: a #GSocket
   * @buffer: (array length=size): the buffer containing the data to send.
   * @size: the number of bytes to send
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Tries to send @size bytes from @buffer on the socket. This is
   * mainly used by connection-oriented sockets; it is identical to
   * g_socket_send_to() with @address set to %NULL.
   *
   * If the socket is in blocking mode the call will block until there is
   * space for the data in the socket queue. If there is no space available
   * and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
   * will be returned. To be notified when space is available, wait for the
   * %G_IO_OUT condition. Note though that you may still receive
   * %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously
   * notified of a %G_IO_OUT condition. (On Windows in particular, this is
   * very common due to the way the underlying APIs work.)
   *
   * On error -1 is returned and @error is set accordingly.
   *
   * Returns: Number of bytes written (which may be less than @size), or -1
   * on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_send (GSocket       *socket,
  	       const gchar   *buffer,
  	       gsize          size,
  	       GCancellable  *cancellable,
  	       GError       **error)
  {
    return g_socket_send_with_blocking (socket, buffer, size,
  				      socket->priv->blocking,
  				      cancellable, error);
  }
  
  /**
   * g_socket_send_with_blocking:
   * @socket: a #GSocket
   * @buffer: (array length=size): the buffer containing the data to send.
   * @size: the number of bytes to send
   * @blocking: whether to do blocking or non-blocking I/O
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * This behaves exactly the same as g_socket_send(), except that
   * the choice of blocking or non-blocking behavior is determined by
   * the @blocking argument rather than by @socket's properties.
   *
   * Returns: Number of bytes written (which may be less than @size), or -1
   * on error
   *
   * Since: 2.26
   */
  gssize
  g_socket_send_with_blocking (GSocket       *socket,
  			     const gchar   *buffer,
  			     gsize          size,
  			     gboolean       blocking,
  			     GCancellable  *cancellable,
  			     GError       **error)
  {
    gssize ret;
  
    g_return_val_if_fail (G_IS_SOCKET (socket) && buffer != NULL, FALSE);
  
    if (!check_socket (socket, error))
      return -1;
  
    if (g_cancellable_set_error_if_cancelled (cancellable, error))
      return -1;
  
    while (1)
      {
        if (blocking &&
  	  !g_socket_condition_wait (socket,
  				    G_IO_OUT, cancellable, error))
  	return -1;
  
        if ((ret = send (socket->priv->fd, buffer, size, G_SOCKET_DEFAULT_SEND_FLAGS)) < 0)
  	{
  	  int errsv = get_socket_errno ();
  
  	  if (errsv == EINTR)
  	    continue;
  
  #ifdef WSAEWOULDBLOCK
  	  if (errsv == WSAEWOULDBLOCK)
  	    win32_unset_event_mask (socket, FD_WRITE);
  #endif
  
  	  if (blocking)
  	    {
  #ifdef WSAEWOULDBLOCK
  	      if (errsv == WSAEWOULDBLOCK)
  		continue;
  #else
  	      if (errsv == EWOULDBLOCK ||
  		  errsv == EAGAIN)
  		continue;
  #endif
  	    }
  
  	  g_set_error (error, G_IO_ERROR,
  		       socket_io_error_from_errno (errsv),
  		       _("Error sending data: %s"), socket_strerror (errsv));
  	  return -1;
  	}
        break;
      }
  
    return ret;
  }
  
  /**
   * g_socket_send_to:
   * @socket: a #GSocket
   * @address: a #GSocketAddress, or %NULL
   * @buffer: (array length=size): the buffer containing the data to send.
   * @size: the number of bytes to send
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Tries to send @size bytes from @buffer to @address. If @address is
   * %NULL then the message is sent to the default receiver (set by
   * g_socket_connect()).
   *
   * See g_socket_send() for additional information.
   *
   * Returns: Number of bytes written (which may be less than @size), or -1
   * on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_send_to (GSocket         *socket,
  		  GSocketAddress  *address,
  		  const gchar     *buffer,
  		  gsize            size,
  		  GCancellable    *cancellable,
  		  GError         **error)
  {
    GOutputVector v;
  
    v.buffer = buffer;
    v.size = size;
  
    return g_socket_send_message (socket,
  				address,
  				&v, 1,
  				NULL, 0,
  				0,
  				cancellable,
  				error);
  }
  
  /**
   * g_socket_shutdown:
   * @socket: a #GSocket
   * @shutdown_read: whether to shut down the read side
   * @shutdown_write: whether to shut down the write side
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Shut down part of a full-duplex connection.
   *
   * If @shutdown_read is %TRUE then the recieving side of the connection
   * is shut down, and further reading is disallowed.
   *
   * If @shutdown_write is %TRUE then the sending side of the connection
   * is shut down, and further writing is disallowed.
   *
   * It is allowed for both @shutdown_read and @shutdown_write to be %TRUE.
   *
   * One example where this is used is graceful disconnect for TCP connections
   * where you close the sending side, then wait for the other side to close
   * the connection, thus ensuring that the other side saw all sent data.
   *
   * Returns: %TRUE on success, %FALSE on error
   *
   * Since: 2.22
   */
  gboolean
  g_socket_shutdown (GSocket   *socket,
  		   gboolean   shutdown_read,
  		   gboolean   shutdown_write,
  		   GError   **error)
  {
    int how;
  
    g_return_val_if_fail (G_IS_SOCKET (socket), TRUE);
  
    if (!check_socket (socket, error))
      return FALSE;
  
    /* Do nothing? */
    if (!shutdown_read && !shutdown_write)
      return TRUE;
  
  #ifndef G_OS_WIN32
    if (shutdown_read && shutdown_write)
      how = SHUT_RDWR;
    else if (shutdown_read)
      how = SHUT_RD;
    else
      how = SHUT_WR;
  #else
    if (shutdown_read && shutdown_write)
      how = SD_BOTH;
    else if (shutdown_read)
      how = SD_RECEIVE;
    else
      how = SD_SEND;
  #endif
  
    if (shutdown (socket->priv->fd, how) != 0)
      {
        int errsv = get_socket_errno ();
        g_set_error (error, G_IO_ERROR, socket_io_error_from_errno (errsv),
  		   _("Unable to shutdown socket: %s"), socket_strerror (errsv));
        return FALSE;
      }
  
    if (shutdown_read && shutdown_write)
      socket->priv->connected = FALSE;
  
    return TRUE;
  }
  
  /**
   * g_socket_close:
   * @socket: a #GSocket
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Closes the socket, shutting down any active connection.
   *
   * Closing a socket does not wait for all outstanding I/O operations
   * to finish, so the caller should not rely on them to be guaranteed
   * to complete even if the close returns with no error.
   *
   * Once the socket is closed, all other operations will return
   * %G_IO_ERROR_CLOSED. Closing a socket multiple times will not
   * return an error.
   *
   * Sockets will be automatically closed when the last reference
   * is dropped, but you might want to call this function to make sure
   * resources are released as early as possible.
   *
   * Beware that due to the way that TCP works, it is possible for
   * recently-sent data to be lost if either you close a socket while the
   * %G_IO_IN condition is set, or else if the remote connection tries to
   * send something to you after you close the socket but before it has
   * finished reading all of the data you sent. There is no easy generic
   * way to avoid this problem; the easiest fix is to design the network
   * protocol such that the client will never send data "out of turn".
   * Another solution is for the server to half-close the connection by
   * calling g_socket_shutdown() with only the @shutdown_write flag set,
   * and then wait for the client to notice this and close its side of the
   * connection, after which the server can safely call g_socket_close().
   * (This is what #GTcpConnection does if you call
   * g_tcp_connection_set_graceful_disconnect(). But of course, this
   * only works if the client will close its connection after the server
   * does.)
   *
   * Returns: %TRUE on success, %FALSE on error
   *
   * Since: 2.22
   */
  gboolean
  g_socket_close (GSocket  *socket,
  		GError  **error)
  {
    int res;
  
    g_return_val_if_fail (G_IS_SOCKET (socket), TRUE);
  
    if (socket->priv->closed)
      return TRUE; /* Multiple close not an error */
  
    if (!check_socket (socket, error))
      return FALSE;
  
    while (1)
      {
  #ifdef G_OS_WIN32
        res = closesocket (socket->priv->fd);
  #else
        res = close (socket->priv->fd);
  #endif
        if (res == -1)
  	{
  	  int errsv = get_socket_errno ();
  
  	  if (errsv == EINTR)
  	    continue;
  
  	  g_set_error (error, G_IO_ERROR,
  		       socket_io_error_from_errno (errsv),
  		       _("Error closing socket: %s"),
  		       socket_strerror (errsv));
  	  return FALSE;
  	}
        break;
      }
  
    socket->priv->connected = FALSE;
    socket->priv->closed = TRUE;
    if (socket->priv->remote_address)
      {
        g_object_unref (socket->priv->remote_address);
        socket->priv->remote_address = NULL;
      }
  
    return TRUE;
  }
  
  /**
   * g_socket_is_closed:
   * @socket: a #GSocket
   *
   * Checks whether a socket is closed.
   *
   * Returns: %TRUE if socket is closed, %FALSE otherwise
   *
   * Since: 2.22
   */
  gboolean
  g_socket_is_closed (GSocket *socket)
  {
    return socket->priv->closed;
  }
  
  #ifdef G_OS_WIN32
  /* Broken source, used on errors */
  static gboolean
  broken_prepare  (GSource *source,
  		 gint    *timeout)
  {
    return FALSE;
  }
  
  static gboolean
  broken_check (GSource *source)
  {
    return FALSE;
  }
  
  static gboolean
  broken_dispatch (GSource     *source,
  		 GSourceFunc  callback,
  		 gpointer     user_data)
  {
    return TRUE;
  }
  
  static GSourceFuncs broken_funcs =
  {
    broken_prepare,
    broken_check,
    broken_dispatch,
    NULL
  };
  
  static gint
  network_events_for_condition (GIOCondition condition)
  {
    int event_mask = 0;
  
    if (condition & G_IO_IN)
      event_mask |= (FD_READ | FD_ACCEPT);
    if (condition & G_IO_OUT)
      event_mask |= (FD_WRITE | FD_CONNECT);
    event_mask |= FD_CLOSE;
  
    return event_mask;
  }
  
  static void
  ensure_event (GSocket *socket)
  {
    if (socket->priv->event == WSA_INVALID_EVENT)
      socket->priv->event = WSACreateEvent();
  }
  
  static void
  update_select_events (GSocket *socket)
  {
    int event_mask;
    GIOCondition *ptr;
    GList *l;
    WSAEVENT event;
  
    ensure_event (socket);
  
    event_mask = 0;
    for (l = socket->priv->requested_conditions; l != NULL; l = l->next)
      {
        ptr = l->data;
        event_mask |= network_events_for_condition (*ptr);
      }
  
    if (event_mask != socket->priv->selected_events)
      {
        /* If no events selected, disable event so we can unset
  	 nonblocking mode */
  
        if (event_mask == 0)
  	event = NULL;
        else
  	event = socket->priv->event;
  
        if (WSAEventSelect (socket->priv->fd, event, event_mask) == 0)
  	socket->priv->selected_events = event_mask;
      }
  }
  
  static void
  add_condition_watch (GSocket      *socket,
  		     GIOCondition *condition)
  {
    g_assert (g_list_find (socket->priv->requested_conditions, condition) == NULL);
  
    socket->priv->requested_conditions =
      g_list_prepend (socket->priv->requested_conditions, condition);
  
    update_select_events (socket);
  }
  
  static void
  remove_condition_watch (GSocket      *socket,
  			GIOCondition *condition)
  {
    g_assert (g_list_find (socket->priv->requested_conditions, condition) != NULL);
  
    socket->priv->requested_conditions =
      g_list_remove (socket->priv->requested_conditions, condition);
  
    update_select_events (socket);
  }
  
  static GIOCondition
  update_condition (GSocket *socket)
  {
    WSANETWORKEVENTS events;
    GIOCondition condition;
  
    if (WSAEnumNetworkEvents (socket->priv->fd,
  			    socket->priv->event,
  			    &events) == 0)
      {
        socket->priv->current_events |= events.lNetworkEvents;
        if (events.lNetworkEvents & FD_WRITE &&
  	  events.iErrorCode[FD_WRITE_BIT] != 0)
  	socket->priv->current_errors |= FD_WRITE;
        if (events.lNetworkEvents & FD_CONNECT &&
  	  events.iErrorCode[FD_CONNECT_BIT] != 0)
  	socket->priv->current_errors |= FD_CONNECT;
      }
  
    condition = 0;
    if (socket->priv->current_events & (FD_READ | FD_ACCEPT))
      condition |= G_IO_IN;
  
    if (socket->priv->current_events & FD_CLOSE ||
        socket->priv->closed)
      condition |= G_IO_HUP;
  
    /* Never report both G_IO_OUT and HUP, these are
       mutually exclusive (can't write to a closed socket) */
    if ((condition & G_IO_HUP) == 0 &&
        socket->priv->current_events & FD_WRITE)
      {
        if (socket->priv->current_errors & FD_WRITE)
  	condition |= G_IO_ERR;
        else
  	condition |= G_IO_OUT;
      }
    else
      {
        if (socket->priv->current_events & FD_CONNECT)
  	{
  	  if (socket->priv->current_errors & FD_CONNECT)
  	    condition |= (G_IO_HUP | G_IO_ERR);
  	  else
  	    condition |= G_IO_OUT;
  	}
      }
  
    return condition;
  }
  #endif
  
  typedef struct {
    GSource       source;
    GPollFD       pollfd;
    GSocket      *socket;
    GIOCondition  condition;
    GCancellable *cancellable;
    GPollFD       cancel_pollfd;
    gint64        timeout_time;
  } GSocketSource;
  
  static gboolean
  socket_source_prepare (GSource *source,
  		       gint    *timeout)
  {
    GSocketSource *socket_source = (GSocketSource *)source;
  
    if (g_cancellable_is_cancelled (socket_source->cancellable))
      return TRUE;
  
    if (socket_source->timeout_time)
      {
        gint64 now;
  
        now = g_source_get_time (source);
        /* Round up to ensure that we don't try again too early */
        *timeout = (socket_source->timeout_time - now + 999) / 1000;
        if (*timeout < 0)
          {
            socket_source->socket->priv->timed_out = TRUE;
            socket_source->pollfd.revents = socket_source->condition & (G_IO_IN | G_IO_OUT);
            *timeout = 0;
            return TRUE;
          }
      }
    else
      *timeout = -1;
  
  #ifdef G_OS_WIN32
    socket_source->pollfd.revents = update_condition (socket_source->socket);
  #endif
  
    if ((socket_source->condition & socket_source->pollfd.revents) != 0)
      return TRUE;
  
    return FALSE;
  }
  
  static gboolean
  socket_source_check (GSource *source)
  {
    int timeout;
  
    return socket_source_prepare (source, &timeout);
  }
  
  static gboolean
  socket_source_dispatch (GSource     *source,
  			GSourceFunc  callback,
  			gpointer     user_data)
  {
    GSocketSourceFunc func = (GSocketSourceFunc)callback;
    GSocketSource *socket_source = (GSocketSource *)source;
  
  #ifdef G_OS_WIN32
    socket_source->pollfd.revents = update_condition (socket_source->socket);
  #endif
  
    return (*func) (socket_source->socket,
  		  socket_source->pollfd.revents & socket_source->condition,
  		  user_data);
  }
  
  static void
  socket_source_finalize (GSource *source)
  {
    GSocketSource *socket_source = (GSocketSource *)source;
    GSocket *socket;
  
    socket = socket_source->socket;
  
  #ifdef G_OS_WIN32
    remove_condition_watch (socket, &socket_source->condition);
  #endif
  
    g_object_unref (socket);
  
    if (socket_source->cancellable)
      {
        g_cancellable_release_fd (socket_source->cancellable);
        g_object_unref (socket_source->cancellable);
      }
  }
  
  static gboolean
  socket_source_closure_callback (GSocket      *socket,
  				GIOCondition  condition,
  				gpointer      data)
  {
    GClosure *closure = data;
  
    GValue params[2] = { { 0, }, { 0, } };
    GValue result_value = { 0, };
    gboolean result;
  
    g_value_init (&result_value, G_TYPE_BOOLEAN);
  
    g_value_init (&params[0], G_TYPE_SOCKET);
    g_value_set_object (&params[0], socket);
    g_value_init (&params[1], G_TYPE_IO_CONDITION);
    g_value_set_flags (&params[1], condition);
  
    g_closure_invoke (closure, &result_value, 2, params, NULL);
  
    result = g_value_get_boolean (&result_value);
    g_value_unset (&result_value);
    g_value_unset (&params[0]);
    g_value_unset (&params[1]);
  
    return result;
  }
  
  static GSourceFuncs socket_source_funcs =
  {
    socket_source_prepare,
    socket_source_check,
    socket_source_dispatch,
    socket_source_finalize,
    (GSourceFunc)socket_source_closure_callback,
    (GSourceDummyMarshal)_gio_marshal_BOOLEAN__FLAGS,
  };
  
  static GSource *
  socket_source_new (GSocket      *socket,
  		   GIOCondition  condition,
  		   GCancellable *cancellable)
  {
    GSource *source;
    GSocketSource *socket_source;
  
  #ifdef G_OS_WIN32
    ensure_event (socket);
  
    if (socket->priv->event == WSA_INVALID_EVENT)
      {
        g_warning ("Failed to create WSAEvent");
        return g_source_new (&broken_funcs, sizeof (GSource));
      }
  #endif
  
    condition |= G_IO_HUP | G_IO_ERR;
  
    source = g_source_new (&socket_source_funcs, sizeof (GSocketSource));
    g_source_set_name (source, "GSocket");
    socket_source = (GSocketSource *)source;
  
    socket_source->socket = g_object_ref (socket);
    socket_source->condition = condition;
  
    if (g_cancellable_make_pollfd (cancellable,
                                   &socket_source->cancel_pollfd))
      {
        socket_source->cancellable = g_object_ref (cancellable);
        g_source_add_poll (source, &socket_source->cancel_pollfd);
      }
  
  #ifdef G_OS_WIN32
    add_condition_watch (socket, &socket_source->condition);
    socket_source->pollfd.fd = (gintptr) socket->priv->event;
  #else
    socket_source->pollfd.fd = socket->priv->fd;
  #endif
  
    socket_source->pollfd.events = condition;
    socket_source->pollfd.revents = 0;
    g_source_add_poll (source, &socket_source->pollfd);
  
    if (socket->priv->timeout)
      socket_source->timeout_time = g_get_monotonic_time () +
                                    socket->priv->timeout * 1000000;
  
    else
      socket_source->timeout_time = 0;
  
    return source;
  }
  
  /**
   * g_socket_create_source: (skip)
   * @socket: a #GSocket
   * @condition: a #GIOCondition mask to monitor
   * @cancellable: (allow-none): a %GCancellable or %NULL
   *
   * Creates a %GSource that can be attached to a %GMainContext to monitor
   * for the availibility of the specified @condition on the socket.
   *
   * The callback on the source is of the #GSocketSourceFunc type.
   *
   * It is meaningless to specify %G_IO_ERR or %G_IO_HUP in @condition;
   * these conditions will always be reported output if they are true.
   *
   * @cancellable if not %NULL can be used to cancel the source, which will
   * cause the source to trigger, reporting the current condition (which
   * is likely 0 unless cancellation happened at the same time as a
   * condition change). You can check for this in the callback using
   * g_cancellable_is_cancelled().
   *
   * If @socket has a timeout set, and it is reached before @condition
   * occurs, the source will then trigger anyway, reporting %G_IO_IN or
   * %G_IO_OUT depending on @condition. However, @socket will have been
   * marked as having had a timeout, and so the next #GSocket I/O method
   * you call will then fail with a %G_IO_ERROR_TIMED_OUT.
   *
   * Returns: (transfer full): a newly allocated %GSource, free with g_source_unref().
   *
   * Since: 2.22
   */
  GSource *
  g_socket_create_source (GSocket      *socket,
  			GIOCondition  condition,
  			GCancellable *cancellable)
  {
    g_return_val_if_fail (G_IS_SOCKET (socket) && (cancellable == NULL || G_IS_CANCELLABLE (cancellable)), NULL);
  
    return socket_source_new (socket, condition, cancellable);
  }
  
  /**
   * g_socket_condition_check:
   * @socket: a #GSocket
   * @condition: a #GIOCondition mask to check
   *
   * Checks on the readiness of @socket to perform operations.
   * The operations specified in @condition are checked for and masked
   * against the currently-satisfied conditions on @socket. The result
   * is returned.
   *
   * Note that on Windows, it is possible for an operation to return
   * %G_IO_ERROR_WOULD_BLOCK even immediately after
   * g_socket_condition_check() has claimed that the socket is ready for
   * writing. Rather than calling g_socket_condition_check() and then
   * writing to the socket if it succeeds, it is generally better to
   * simply try writing to the socket right away, and try again later if
   * the initial attempt returns %G_IO_ERROR_WOULD_BLOCK.
   *
   * It is meaningless to specify %G_IO_ERR or %G_IO_HUP in condition;
   * these conditions will always be set in the output if they are true.
   *
   * This call never blocks.
   *
   * Returns: the @GIOCondition mask of the current state
   *
   * Since: 2.22
   */
  GIOCondition
  g_socket_condition_check (GSocket      *socket,
  			  GIOCondition  condition)
  {
    if (!check_socket (socket, NULL))
      return 0;
  
  #ifdef G_OS_WIN32
    {
      GIOCondition current_condition;
  
      condition |= G_IO_ERR | G_IO_HUP;
  
      add_condition_watch (socket, &condition);
      current_condition = update_condition (socket);
      remove_condition_watch (socket, &condition);
      return condition & current_condition;
    }
  #else
    {
      GPollFD poll_fd;
      gint result;
      poll_fd.fd = socket->priv->fd;
      poll_fd.events = condition;
  
      do
        result = g_poll (&poll_fd, 1, 0);
      while (result == -1 && get_socket_errno () == EINTR);
  
      return poll_fd.revents;
    }
  #endif
  }
  
  /**
   * g_socket_condition_wait:
   * @socket: a #GSocket
   * @condition: a #GIOCondition mask to wait for
   * @cancellable: (allow-none): a #GCancellable, or %NULL
   * @error: a #GError pointer, or %NULL
   *
   * Waits for @condition to become true on @socket. When the condition
   * is met, %TRUE is returned.
   *
   * If @cancellable is cancelled before the condition is met, or if the
   * socket has a timeout set and it is reached before the condition is
   * met, then %FALSE is returned and @error, if non-%NULL, is set to
   * the appropriate value (%G_IO_ERROR_CANCELLED or
   * %G_IO_ERROR_TIMED_OUT).
   *
   * Returns: %TRUE if the condition was met, %FALSE otherwise
   *
   * Since: 2.22
   */
  gboolean
  g_socket_condition_wait (GSocket       *socket,
  			 GIOCondition   condition,
  			 GCancellable  *cancellable,
  			 GError       **error)
  {
    if (!check_socket (socket, error))
      return FALSE;
  
    if (g_cancellable_set_error_if_cancelled (cancellable, error))
      return FALSE;
  
  #ifdef G_OS_WIN32
    {
      GIOCondition current_condition;
      WSAEVENT events[2];
      DWORD res, timeout;
      GPollFD cancel_fd;
      int num_events;
  
      /* Always check these */
      condition |=  G_IO_ERR | G_IO_HUP;
  
      add_condition_watch (socket, &condition);
  
      num_events = 0;
      events[num_events++] = socket->priv->event;
  
      if (g_cancellable_make_pollfd (cancellable, &cancel_fd))
        events[num_events++] = (WSAEVENT)cancel_fd.fd;
  
      if (socket->priv->timeout)
        timeout = socket->priv->timeout * 1000;
      else
        timeout = WSA_INFINITE;
  
      current_condition = update_condition (socket);
      while ((condition & current_condition) == 0)
        {
  	res = WSAWaitForMultipleEvents(num_events, events,
  				       FALSE, timeout, FALSE);
  	if (res == WSA_WAIT_FAILED)
  	  {
  	    int errsv = get_socket_errno ();
  
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Waiting for socket condition: %s"),
  			 socket_strerror (errsv));
  	    break;
  	  }
  	else if (res == WSA_WAIT_TIMEOUT)
  	  {
  	    g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_TIMED_OUT,
  				 _("Socket I/O timed out"));
  	    break;
  	  }
  
  	if (g_cancellable_set_error_if_cancelled (cancellable, error))
  	  break;
  
  	current_condition = update_condition (socket);
        }
      remove_condition_watch (socket, &condition);
      if (num_events > 1)
        g_cancellable_release_fd (cancellable);
  
      return (condition & current_condition) != 0;
    }
  #else
    {
      GPollFD poll_fd[2];
      gint result;
      gint num;
      gint timeout;
  
      poll_fd[0].fd = socket->priv->fd;
      poll_fd[0].events = condition;
      num = 1;
  
      if (g_cancellable_make_pollfd (cancellable, &poll_fd[1]))
        num++;
  
      if (socket->priv->timeout)
        timeout = socket->priv->timeout * 1000;
      else
        timeout = -1;
  
      do
        result = g_poll (poll_fd, num, timeout);
      while (result == -1 && get_socket_errno () == EINTR);
      
      if (num > 1)
        g_cancellable_release_fd (cancellable);
  
      if (result == 0)
        {
  	g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_TIMED_OUT,
  			     _("Socket I/O timed out"));
  	return FALSE;
        }
  
      return !g_cancellable_set_error_if_cancelled (cancellable, error);
    }
    #endif
  }
  
  /**
   * g_socket_send_message:
   * @socket: a #GSocket
   * @address: a #GSocketAddress, or %NULL
   * @vectors: (array length=num_vectors): an array of #GOutputVector structs
   * @num_vectors: the number of elements in @vectors, or -1
   * @messages: (array length=num_messages) (allow-none): a pointer to an
   *   array of #GSocketControlMessages, or %NULL.
   * @num_messages: number of elements in @messages, or -1.
   * @flags: an int containing #GSocketMsgFlags flags
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Send data to @address on @socket.  This is the most complicated and
   * fully-featured version of this call. For easier use, see
   * g_socket_send() and g_socket_send_to().
   *
   * If @address is %NULL then the message is sent to the default receiver
   * (set by g_socket_connect()).
   *
   * @vectors must point to an array of #GOutputVector structs and
   * @num_vectors must be the length of this array. (If @num_vectors is -1,
   * then @vectors is assumed to be terminated by a #GOutputVector with a
   * %NULL buffer pointer.) The #GOutputVector structs describe the buffers
   * that the sent data will be gathered from. Using multiple
   * #GOutputVector<!-- -->s is more memory-efficient than manually copying
   * data from multiple sources into a single buffer, and more
   * network-efficient than making multiple calls to g_socket_send().
   *
   * @messages, if non-%NULL, is taken to point to an array of @num_messages
   * #GSocketControlMessage instances. These correspond to the control
   * messages to be sent on the socket.
   * If @num_messages is -1 then @messages is treated as a %NULL-terminated
   * array.
   *
   * @flags modify how the message is sent. The commonly available arguments
   * for this are available in the #GSocketMsgFlags enum, but the
   * values there are the same as the system values, and the flags
   * are passed in as-is, so you can pass in system-specific flags too.
   *
   * If the socket is in blocking mode the call will block until there is
   * space for the data in the socket queue. If there is no space available
   * and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
   * will be returned. To be notified when space is available, wait for the
   * %G_IO_OUT condition. Note though that you may still receive
   * %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously
   * notified of a %G_IO_OUT condition. (On Windows in particular, this is
   * very common due to the way the underlying APIs work.)
   *
   * On error -1 is returned and @error is set accordingly.
   *
   * Returns: Number of bytes written (which may be less than @size), or -1
   * on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_send_message (GSocket                *socket,
  		       GSocketAddress         *address,
  		       GOutputVector          *vectors,
  		       gint                    num_vectors,
  		       GSocketControlMessage **messages,
  		       gint                    num_messages,
  		       gint                    flags,
  		       GCancellable           *cancellable,
  		       GError                **error)
  {
    GOutputVector one_vector;
    char zero;
  
    if (!check_socket (socket, error))
      return -1;
  
    if (g_cancellable_set_error_if_cancelled (cancellable, error))
      return -1;
  
    if (num_vectors == -1)
      {
        for (num_vectors = 0;
  	   vectors[num_vectors].buffer != NULL;
  	   num_vectors++)
  	;
      }
  
    if (num_messages == -1)
      {
        for (num_messages = 0;
  	   messages != NULL && messages[num_messages] != NULL;
  	   num_messages++)
  	;
      }
  
    if (num_vectors == 0)
      {
        zero = '\0';
  
        one_vector.buffer = &zero;
        one_vector.size = 1;
        num_vectors = 1;
        vectors = &one_vector;
      }
  
  #ifndef G_OS_WIN32
    {
      struct msghdr msg;
      gssize result;
  
     msg.msg_flags = 0;
  
      /* name */
      if (address)
        {
  	msg.msg_namelen = g_socket_address_get_native_size (address);
  	msg.msg_name = g_alloca (msg.msg_namelen);
  	if (!g_socket_address_to_native (address, msg.msg_name, msg.msg_namelen, error))
  	  return -1;
        }
      else
        {
  	msg.msg_name = NULL;
  	msg.msg_namelen = 0;
        }
  
      /* iov */
      {
        /* this entire expression will be evaluated at compile time */
        if (sizeof *msg.msg_iov == sizeof *vectors &&
  	  sizeof msg.msg_iov->iov_base == sizeof vectors->buffer &&
  	  G_STRUCT_OFFSET (struct iovec, iov_base) ==
  	  G_STRUCT_OFFSET (GOutputVector, buffer) &&
  	  sizeof msg.msg_iov->iov_len == sizeof vectors->size &&
  	  G_STRUCT_OFFSET (struct iovec, iov_len) ==
  	  G_STRUCT_OFFSET (GOutputVector, size))
  	/* ABI is compatible */
  	{
  	  msg.msg_iov = (struct iovec *) vectors;
  	  msg.msg_iovlen = num_vectors;
  	}
        else
  	/* ABI is incompatible */
  	{
  	  gint i;
  
  	  msg.msg_iov = g_newa (struct iovec, num_vectors);
  	  for (i = 0; i < num_vectors; i++)
  	    {
  	      msg.msg_iov[i].iov_base = (void *) vectors[i].buffer;
  	      msg.msg_iov[i].iov_len = vectors[i].size;
  	    }
  	  msg.msg_iovlen = num_vectors;
  	}
      }
  
      /* control */
      {
        struct cmsghdr *cmsg;
        gint i;
  
        msg.msg_controllen = 0;
        for (i = 0; i < num_messages; i++)
  	msg.msg_controllen += CMSG_SPACE (g_socket_control_message_get_size (messages[i]));
  
        if (msg.msg_controllen == 0)
          msg.msg_control = NULL;
        else
          {
            msg.msg_control = g_alloca (msg.msg_controllen);
            memset (msg.msg_control, '\0', msg.msg_controllen);
          }
  
        cmsg = CMSG_FIRSTHDR (&msg);
        for (i = 0; i < num_messages; i++)
  	{
  	  cmsg->cmsg_level = g_socket_control_message_get_level (messages[i]);
  	  cmsg->cmsg_type = g_socket_control_message_get_msg_type (messages[i]);
  	  cmsg->cmsg_len = CMSG_LEN (g_socket_control_message_get_size (messages[i]));
  	  g_socket_control_message_serialize (messages[i],
  					      CMSG_DATA (cmsg));
  	  cmsg = CMSG_NXTHDR (&msg, cmsg);
  	}
        g_assert (cmsg == NULL);
      }
  
      while (1)
        {
  	if (socket->priv->blocking &&
  	    !g_socket_condition_wait (socket,
  				      G_IO_OUT, cancellable, error))
  	  return -1;
  
  	result = sendmsg (socket->priv->fd, &msg, flags | G_SOCKET_DEFAULT_SEND_FLAGS);
  	if (result < 0)
  	  {
  	    int errsv = get_socket_errno ();
  
  	    if (errsv == EINTR)
  	      continue;
  
  	    if (socket->priv->blocking &&
  		(errsv == EWOULDBLOCK ||
  		 errsv == EAGAIN))
  	      continue;
  
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Error sending message: %s"), socket_strerror (errsv));
  
  	    return -1;
  	  }
  	break;
        }
  
      return result;
    }
  #else
    {
      struct sockaddr_storage addr;
      guint addrlen;
      DWORD bytes_sent;
      int result;
      WSABUF *bufs;
      gint i;
  
      /* Win32 doesn't support control messages.
         Actually this is possible for raw and datagram sockets
         via WSASendMessage on Vista or later, but that doesn't
         seem very useful */
      if (num_messages != 0)
        {
          g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
                               _("GSocketControlMessage not supported on windows"));
  	return -1;
        }
  
      /* iov */
      bufs = g_newa (WSABUF, num_vectors);
      for (i = 0; i < num_vectors; i++)
        {
  	bufs[i].buf = (char *)vectors[i].buffer;
  	bufs[i].len = (gulong)vectors[i].size;
        }
  
      /* name */
      addrlen = 0; /* Avoid warning */
      if (address)
        {
  	addrlen = g_socket_address_get_native_size (address);
  	if (!g_socket_address_to_native (address, &addr, sizeof addr, error))
  	  return -1;
        }
  
      while (1)
        {
  	if (socket->priv->blocking &&
  	    !g_socket_condition_wait (socket,
  				      G_IO_OUT, cancellable, error))
  	  return -1;
  
  	if (address)
  	  result = WSASendTo (socket->priv->fd,
  			      bufs, num_vectors,
  			      &bytes_sent, flags,
  			      (const struct sockaddr *)&addr, addrlen,
  			      NULL, NULL);
  	else
  	  result = WSASend (socket->priv->fd,
  			    bufs, num_vectors,
  			    &bytes_sent, flags,
  			    NULL, NULL);
  
  	if (result != 0)
  	  {
  	    int errsv = get_socket_errno ();
  
  	    if (errsv == WSAEINTR)
  	      continue;
  
  	    if (errsv == WSAEWOULDBLOCK)
  	      win32_unset_event_mask (socket, FD_WRITE);
  
  	    if (socket->priv->blocking &&
  		errsv == WSAEWOULDBLOCK)
  	      continue;
  
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Error sending message: %s"), socket_strerror (errsv));
  
  	    return -1;
  	  }
  	break;
        }
  
      return bytes_sent;
    }
  #endif
  }
  
  /**
   * g_socket_receive_message:
   * @socket: a #GSocket
   * @address: a pointer to a #GSocketAddress pointer, or %NULL
   * @vectors: (array length=num_vectors): an array of #GInputVector structs
   * @num_vectors: the number of elements in @vectors, or -1
   * @messages: (array length=num_messages) (allow-none): a pointer which
   *    may be filled with an array of #GSocketControlMessages, or %NULL
   * @num_messages: a pointer which will be filled with the number of
   *    elements in @messages, or %NULL
   * @flags: a pointer to an int containing #GSocketMsgFlags flags
   * @cancellable: (allow-none): a %GCancellable or %NULL
   * @error: a #GError pointer, or %NULL
   *
   * Receive data from a socket.  This is the most complicated and
   * fully-featured version of this call. For easier use, see
   * g_socket_receive() and g_socket_receive_from().
   *
   * If @address is non-%NULL then @address will be set equal to the
   * source address of the received packet.
   * @address is owned by the caller.
   *
   * @vector must point to an array of #GInputVector structs and
   * @num_vectors must be the length of this array.  These structs
   * describe the buffers that received data will be scattered into.
   * If @num_vectors is -1, then @vectors is assumed to be terminated
   * by a #GInputVector with a %NULL buffer pointer.
   *
   * As a special case, if @num_vectors is 0 (in which case, @vectors
   * may of course be %NULL), then a single byte is received and
   * discarded. This is to facilitate the common practice of sending a
   * single '\0' byte for the purposes of transferring ancillary data.
   *
   * @messages, if non-%NULL, will be set to point to a newly-allocated
   * array of #GSocketControlMessage instances or %NULL if no such
   * messages was received. These correspond to the control messages
   * received from the kernel, one #GSocketControlMessage per message
   * from the kernel. This array is %NULL-terminated and must be freed
   * by the caller using g_free() after calling g_object_unref() on each
   * element. If @messages is %NULL, any control messages received will
   * be discarded.
   *
   * @num_messages, if non-%NULL, will be set to the number of control
   * messages received.
   *
   * If both @messages and @num_messages are non-%NULL, then
   * @num_messages gives the number of #GSocketControlMessage instances
   * in @messages (ie: not including the %NULL terminator).
   *
   * @flags is an in/out parameter. The commonly available arguments
   * for this are available in the #GSocketMsgFlags enum, but the
   * values there are the same as the system values, and the flags
   * are passed in as-is, so you can pass in system-specific flags too
   * (and g_socket_receive_message() may pass system-specific flags out).
   *
   * As with g_socket_receive(), data may be discarded if @socket is
   * %G_SOCKET_TYPE_DATAGRAM or %G_SOCKET_TYPE_SEQPACKET and you do not
   * provide enough buffer space to read a complete message. You can pass
   * %G_SOCKET_MSG_PEEK in @flags to peek at the current message without
   * removing it from the receive queue, but there is no portable way to find
   * out the length of the message other than by reading it into a
   * sufficiently-large buffer.
   *
   * If the socket is in blocking mode the call will block until there
   * is some data to receive or there is an error. If there is no data
   * available and the socket is in non-blocking mode, a
   * %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when
   * data is available, wait for the %G_IO_IN condition.
   *
   * On error -1 is returned and @error is set accordingly.
   *
   * Returns: Number of bytes read, or -1 on error
   *
   * Since: 2.22
   */
  gssize
  g_socket_receive_message (GSocket                 *socket,
  			  GSocketAddress         **address,
  			  GInputVector            *vectors,
  			  gint                     num_vectors,
  			  GSocketControlMessage ***messages,
  			  gint                    *num_messages,
  			  gint                    *flags,
  			  GCancellable            *cancellable,
  			  GError                 **error)
  {
    GInputVector one_vector;
    char one_byte;
  
    if (!check_socket (socket, error))
      return -1;
  
    if (g_cancellable_set_error_if_cancelled (cancellable, error))
      return -1;
  
    if (num_vectors == -1)
      {
        for (num_vectors = 0;
  	   vectors[num_vectors].buffer != NULL;
  	   num_vectors++)
  	;
      }
  
    if (num_vectors == 0)
      {
        one_vector.buffer = &one_byte;
        one_vector.size = 1;
        num_vectors = 1;
        vectors = &one_vector;
      }
  
  #ifndef G_OS_WIN32
    {
      struct msghdr msg;
      gssize result;
      struct sockaddr_storage one_sockaddr;
  
      /* name */
      if (address)
        {
  	msg.msg_name = &one_sockaddr;
  	msg.msg_namelen = sizeof (struct sockaddr_storage);
        }
      else
        {
  	msg.msg_name = NULL;
  	msg.msg_namelen = 0;
        }
  
      /* iov */
      /* this entire expression will be evaluated at compile time */
      if (sizeof *msg.msg_iov == sizeof *vectors &&
  	sizeof msg.msg_iov->iov_base == sizeof vectors->buffer &&
  	G_STRUCT_OFFSET (struct iovec, iov_base) ==
  	G_STRUCT_OFFSET (GInputVector, buffer) &&
  	sizeof msg.msg_iov->iov_len == sizeof vectors->size &&
  	G_STRUCT_OFFSET (struct iovec, iov_len) ==
  	G_STRUCT_OFFSET (GInputVector, size))
        /* ABI is compatible */
        {
  	msg.msg_iov = (struct iovec *) vectors;
  	msg.msg_iovlen = num_vectors;
        }
      else
        /* ABI is incompatible */
        {
  	gint i;
  
  	msg.msg_iov = g_newa (struct iovec, num_vectors);
  	for (i = 0; i < num_vectors; i++)
  	  {
  	    msg.msg_iov[i].iov_base = vectors[i].buffer;
  	    msg.msg_iov[i].iov_len = vectors[i].size;
  	  }
  	msg.msg_iovlen = num_vectors;
        }
  
      /* control */
      msg.msg_control = g_alloca (2048);
      msg.msg_controllen = 2048;
  
      /* flags */
      if (flags != NULL)
        msg.msg_flags = *flags;
      else
        msg.msg_flags = 0;
  
      /* do it */
      while (1)
        {
  	if (socket->priv->blocking &&
  	    !g_socket_condition_wait (socket,
  				      G_IO_IN, cancellable, error))
  	  return -1;
  
  	result = recvmsg (socket->priv->fd, &msg, msg.msg_flags);
  
  	if (result < 0)
  	  {
  	    int errsv = get_socket_errno ();
  
  	    if (errsv == EINTR)
  	      continue;
  
  	    if (socket->priv->blocking &&
  		(errsv == EWOULDBLOCK ||
  		 errsv == EAGAIN))
  	      continue;
  
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Error receiving message: %s"), socket_strerror (errsv));
  
  	    return -1;
  	  }
  	break;
        }
  
      /* decode address */
      if (address != NULL)
        {
  	if (msg.msg_namelen > 0)
  	  *address = g_socket_address_new_from_native (msg.msg_name,
  						       msg.msg_namelen);
  	else
  	  *address = NULL;
        }
  
      /* decode control messages */
      {
        GPtrArray *my_messages = NULL;
        const gchar *scm_pointer;
        struct cmsghdr *cmsg;
        gsize scm_size;
  
        scm_pointer = (const gchar *) msg.msg_control;
        scm_size = msg.msg_controllen;
  
        for (cmsg = CMSG_FIRSTHDR (&msg); cmsg; cmsg = CMSG_NXTHDR (&msg, cmsg))
  	{
  	  GSocketControlMessage *message;
  
  	  message = g_socket_control_message_deserialize (cmsg->cmsg_level,
  							  cmsg->cmsg_type,
  							  cmsg->cmsg_len - ((char *)CMSG_DATA (cmsg) - (char *)cmsg),
  							  CMSG_DATA (cmsg));
  	  if (message == NULL)
  	    /* We've already spewed about the problem in the
  	       deserialization code, so just continue */
  	    continue;
  
  	  if (messages == NULL)
  	    {
  	      /* we have to do it this way if the user ignores the
  	       * messages so that we will close any received fds.
  	       */
  	      g_object_unref (message);
  	    }
  	  else
  	    {
  	      if (my_messages == NULL)
  		my_messages = g_ptr_array_new ();
  	      g_ptr_array_add (my_messages, message);
  	    }
  	}
  
        if (num_messages)
  	*num_messages = my_messages != NULL ? my_messages->len : 0;
  
        if (messages)
  	{
  	  if (my_messages == NULL)
  	    {
  	      *messages = NULL;
  	    }
  	  else
  	    {
  	      g_ptr_array_add (my_messages, NULL);
  	      *messages = (GSocketControlMessage **) g_ptr_array_free (my_messages, FALSE);
  	    }
  	}
        else
  	{
  	  g_assert (my_messages == NULL);
  	}
      }
  
      /* capture the flags */
      if (flags != NULL)
        *flags = msg.msg_flags;
  
      return result;
    }
  #else
    {
      struct sockaddr_storage addr;
      int addrlen;
      DWORD bytes_received;
      DWORD win_flags;
      int result;
      WSABUF *bufs;
      gint i;
  
      /* iov */
      bufs = g_newa (WSABUF, num_vectors);
      for (i = 0; i < num_vectors; i++)
        {
  	bufs[i].buf = (char *)vectors[i].buffer;
  	bufs[i].len = (gulong)vectors[i].size;
        }
  
      /* flags */
      if (flags != NULL)
        win_flags = *flags;
      else
        win_flags = 0;
  
      /* do it */
      while (1)
        {
  	if (socket->priv->blocking &&
  	    !g_socket_condition_wait (socket,
  				      G_IO_IN, cancellable, error))
  	  return -1;
  
  	addrlen = sizeof addr;
  	if (address)
  	  result = WSARecvFrom (socket->priv->fd,
  				bufs, num_vectors,
  				&bytes_received, &win_flags,
  				(struct sockaddr *)&addr, &addrlen,
  				NULL, NULL);
  	else
  	  result = WSARecv (socket->priv->fd,
  			    bufs, num_vectors,
  			    &bytes_received, &win_flags,
  			    NULL, NULL);
  	if (result != 0)
  	  {
  	    int errsv = get_socket_errno ();
  
  	    if (errsv == WSAEINTR)
  	      continue;
  
  	    win32_unset_event_mask (socket, FD_READ);
  
  	    if (socket->priv->blocking &&
  		errsv == WSAEWOULDBLOCK)
  	      continue;
  
  	    g_set_error (error, G_IO_ERROR,
  			 socket_io_error_from_errno (errsv),
  			 _("Error receiving message: %s"), socket_strerror (errsv));
  
  	    return -1;
  	  }
  	win32_unset_event_mask (socket, FD_READ);
  	break;
        }
  
      /* decode address */
      if (address != NULL)
        {
  	if (addrlen > 0)
  	  *address = g_socket_address_new_from_native (&addr, addrlen);
  	else
  	  *address = NULL;
        }
  
      /* capture the flags */
      if (flags != NULL)
        *flags = win_flags;
  
      if (messages != NULL)
        *messages = NULL;
      if (num_messages != NULL)
        *num_messages = 0;
  
      return bytes_received;
    }
  #endif
  }
  
  /**
   * g_socket_get_credentials:
   * @socket: a #GSocket.
   * @error: #GError for error reporting, or %NULL to ignore.
   *
   * Returns the credentials of the foreign process connected to this
   * socket, if any (e.g. it is only supported for %G_SOCKET_FAMILY_UNIX
   * sockets).
   *
   * If this operation isn't supported on the OS, the method fails with
   * the %G_IO_ERROR_NOT_SUPPORTED error. On Linux this is implemented
   * by reading the %SO_PEERCRED option on the underlying socket.
   *
   * Other ways to obtain credentials from a foreign peer includes the
   * #GUnixCredentialsMessage type and
   * g_unix_connection_send_credentials() /
   * g_unix_connection_receive_credentials() functions.
   *
   * Returns: (transfer full): %NULL if @error is set, otherwise a #GCredentials object
   * that must be freed with g_object_unref().
   *
   * Since: 2.26
   */
  GCredentials *
  g_socket_get_credentials (GSocket   *socket,
                            GError   **error)
  {
    GCredentials *ret;
  
    g_return_val_if_fail (G_IS_SOCKET (socket), NULL);
    g_return_val_if_fail (error == NULL || *error == NULL, NULL);
  
    ret = NULL;
  
  #ifdef __linux__
    {
      struct ucred native_creds;
      socklen_t optlen;
      optlen = sizeof (struct ucred);
      if (getsockopt (socket->priv->fd,
                      SOL_SOCKET,
                      SO_PEERCRED,
                      (void *)&native_creds,
                      &optlen) != 0)
        {
          int errsv = get_socket_errno ();
          g_set_error (error,
                       G_IO_ERROR,
                       socket_io_error_from_errno (errsv),
                       _("Unable to get pending error: %s"),
                       socket_strerror (errsv));
        }
      else
        {
          ret = g_credentials_new ();
          g_credentials_set_native (ret,
                                    G_CREDENTIALS_TYPE_LINUX_UCRED,
                                    &native_creds);
        }
    }
  #else
    g_set_error_literal (error,
                         G_IO_ERROR,
                         G_IO_ERROR_NOT_SUPPORTED,
                         _("g_socket_get_credentials not implemented for this OS"));
  #endif
  
    return ret;
  }
  