hush/include/poll.h
Stephen Heumann 488a238ad7 Add an implementation of poll() written in terms of select(), to work around the lack of poll() on GNO.
This is a BSD-licensed poll() implementation by Brian M. Clapper. Its performance characteristics aren't as good as a "native" poll() would be, but this shouldn't be a problem in practice.
2014-11-03 12:26:43 -06:00

106 lines
3.2 KiB
C

/*---------------------------------------------------------------------------*\
$Id$
NAME
poll - select(2)-based poll() emulation function for BSD systems.
SYNOPSIS
#include "poll.h"
struct pollfd
{
int fd;
short events;
short revents;
}
int poll (struct pollfd *pArray, unsigned long n_fds, int timeout)
DESCRIPTION
This file, and the accompanying "poll.c", implement the System V
poll(2) system call for BSD systems (which typically do not provide
poll()). Poll() provides a method for multiplexing input and output
on multiple open file descriptors; in traditional BSD systems, that
capability is provided by select(). While the semantics of select()
differ from those of poll(), poll() can be readily emulated in terms
of select() -- which is how this function is implemented.
REFERENCES
Stevens, W. Richard. Unix Network Programming. Prentice-Hall, 1990.
NOTES
1. This software requires an ANSI C compiler.
LICENSE
This software is released under the following BSD license, adapted from
http://opensource.org/licenses/bsd-license.php
Copyright (c) 1995-2011, Brian M. Clapper
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the clapper.org nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\*---------------------------------------------------------------------------*/
#ifndef _POLL_EMUL_H_
#define _POLL_EMUL_H_
#define POLLIN 0x01
#define POLLPRI 0x02
#define POLLOUT 0x04
#define POLLERR 0x08
#define POLLHUP 0x10
#define POLLNVAL 0x20
struct pollfd
{
int fd;
short events;
short revents;
};
typedef unsigned long nfds_t;
#ifdef __cplusplus
extern "C"
{
#endif
#if (__STDC__ > 0) || defined(__cplusplus)
extern int poll (struct pollfd *pArray, nfds_t n_fds, int timeout);
#else
extern int poll();
#endif
#ifdef __cplusplus
}
#endif
#endif /* _POLL_EMUL_H_ */