StdLib: Clarify and improve comments.

[mirror_edk2.git] / StdLib / Include / sys / poll.h

/** @file\r
    Definitions in support of the poll() function.\r
\r
 * Copyright (c) 1998 The NetBSD Foundation, Inc.\r
 * All rights reserved.\r
 *\r
 * This code is derived from software contributed to The NetBSD Foundation\r
 * by Charles M. Hannum.\r
 *\r
 * Redistribution and use in source and binary forms, with or without\r
 * modification, are permitted provided that the following conditions\r
 * are met:\r
 * 1. Redistributions of source code must retain the above copyright\r
 *    notice, this list of conditions and the following disclaimer.\r
 * 2. Redistributions in binary form must reproduce the above copyright\r
 *    notice, this list of conditions and the following disclaimer in the\r
 *    documentation and/or other materials provided with the distribution.\r
 * 3. All advertising materials mentioning features or use of this software\r
 *    must display the following acknowledgement:\r
 *  This product includes software developed by the NetBSD\r
 *  Foundation, Inc. and its contributors.\r
 * 4. Neither the name of The NetBSD Foundation nor the names of its\r
 *    contributors may be used to endorse or promote products derived\r
 *    from this software without specific prior written permission.\r
 *\r
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS\r
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED\r
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR\r
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS\r
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR\r
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF\r
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS\r
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN\r
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)\r
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\r
 * POSSIBILITY OF SUCH DAMAGE.\r
\r
    Copyright (c) 2011, Intel Corporation. All rights reserved.<BR>\r
    This program and the accompanying materials are licensed and made available under\r
    the terms and conditions of the BSD License that accompanies this distribution.\r
    The full text of the license may be found at\r
    http://opensource.org/licenses/bsd-license.php.\r
\r
    THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
    WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
    NetBSD: poll.h,v 1.11 2005/12/11 12:25:20 christos Exp\r
**/\r
#ifndef _SYS_POLL_H_\r
#define _SYS_POLL_H_\r
\r
#include <sys/featuretest.h>\r
#include <sys/EfiCdefs.h>\r
\r
typedef unsigned int  nfds_t;\r
\r
struct pollfd {\r
  int   fd;       /* file descriptor */\r
  short events;   /* events to look for */\r
  short revents;  /* events returned */\r
};\r
\r
/*\r
 * Testable events (may be specified in events field).\r
 */\r
#define POLLIN      0x0001\r
#define POLLPRI     0x0002\r
#define POLLOUT     0x0004\r
#define POLLRDNORM  0x0040\r
#define POLLWRNORM  POLLOUT\r
#define POLLRDBAND  0x0080\r
#define POLLWRBAND  0x0100\r
\r
/*\r
 * Non-testable events (ignored in events field, valid in return only).\r
 */\r
#define POLLERR     0x0008\r
#define POLLHUP     0x0010\r
#define POLLNVAL    0x0020    // Invalid parameter in POLL call\r
#define POLL_RETONLY  (POLLERR | POLLHUP | POLLNVAL)\r
\r
/*\r
 * Infinite timeout value.\r
 */\r
#define INFTIM    -1\r
\r
__BEGIN_DECLS\r
int poll(struct pollfd *, nfds_t, int);\r
__END_DECLS\r
\r
#endif /* !_SYS_POLL_H_ */\r