/* 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__ */
