/* gpoll.h - poll(2) support

 * Copyright (C) 2008 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 2.1 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, see <http://www.gnu.org/licenses/>.

 */

#ifndef __G_POLL_H__

#define __G_POLL_H__

#if !defined (__GLIB_H_INSIDE__) && !defined (__G_MAIN_H__) && !defined (GLIB_COMPILATION)

#error "Only <glib.h> can be included directly."

#endif

#include <glibconfig.h>

#include <glib/gtypes.h>

G_BEGIN_DECLS

/* Any definitions using GPollFD or GPollFunc are primarily

 * for Unix and not guaranteed to be the compatible on all

 * operating systems on which GLib runs. Right now, the

 * GLib does use these functions on Win32 as well, but interprets

 * them in a fairly different way than on Unix. If you use

 * these definitions, you are should be prepared to recode

 * for different operating systems.

 *

 * Note that on systems with a working poll(2), that function is used

 * in place of g_poll(). Thus g_poll() must have the same signature as

 * poll(), meaning GPollFD must have the same layout as struct pollfd.

 *

 * On Win32, the fd in a GPollFD should be Win32 HANDLE (*not* a file

 * descriptor as provided by the C runtime) that can be used by

 * MsgWaitForMultipleObjects. This does *not* include file handles

 * from CreateFile, SOCKETs, nor pipe handles. (But you can use

 * WSAEventSelect to signal events when a SOCKET is readable).

 *

 * On Win32, fd can also be the special value G_WIN32_MSG_HANDLE to

 * indicate polling for messages.

 *

 * But note that G_WIN32_MSG_HANDLE GPollFDs should not be used by GDK

 * (GTK) programs, as GDK itself wants to read messages and convert them

 * to GDK events.

 *

 * So, unless you really know what you are doing, it's best not to try

 * to use the main loop polling stuff for your own needs on

 * Windows.

 */

typedef struct _GPollFD GPollFD;

/**

 * GPollFunc:

 * @ufds: an array of #GPollFD elements

 * @nfsd: the number of elements in @ufds

 * @timeout_: the maximum time to wait for an event of the file descriptors.

 *     A negative value indicates an infinite timeout.

 *

 * Specifies the type of function passed to g_main_context_set_poll_func().

 * The semantics of the function should match those of the poll() system call.

 *

 * Returns: the number of #GPollFD elements which have events or errors

 *     reported, or -1 if an error occurred.

 */

typedef gint    (*GPollFunc)    (GPollFD *ufds,

                                 guint    nfsd,

                                 gint     timeout_);

/**

 * GPollFD:

 * @fd: the file descriptor to poll (or a HANDLE on Win32)

 * @events: a bitwise combination from #GIOCondition, specifying which

 *     events should be polled for. Typically for reading from a file

 *     descriptor you would use %G_IO_IN | %G_IO_HUP | %G_IO_ERR, and

 *     for writing you would use %G_IO_OUT | %G_IO_ERR.

 * @revents: a bitwise combination of flags from #GIOCondition, returned

 *     from the poll() function to indicate which events occurred.

 *

 * Represents a file descriptor, which events to poll for, and which events

 * occurred.

 */

struct _GPollFD

{

#if defined (G_OS_WIN32) && GLIB_SIZEOF_VOID_P == 8

#ifndef __GTK_DOC_IGNORE__

  gint64	fd;

#endif

#else

  gint		fd;

#endif

  gushort 	events;

  gushort 	revents;

};

/**

 * G_POLLFD_FORMAT:

 *

 * A format specifier that can be used in printf()-style format strings

 * when printing the @fd member of a #GPollFD.

 */

/* defined in glibconfig.h */

GLIB_AVAILABLE_IN_ALL

gint

g_poll (GPollFD *fds,

	guint    nfds,

	gint     timeout);

G_END_DECLS

#endif /* __G_POLL_H__ */