mbed-os/platform/mbed_poll.h

63 lines
1.9 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2017-2019 ARM Limited
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_POLL_H
#define MBED_POLL_H
#define POLLIN 0x0001 ///< Data may be read without blocking
#define POLLOUT 0x0010 ///< Data may be written without blocking
#define POLLERR 0x1000 ///< An error has occurred on the device or stream
#define POLLHUP 0x2000 ///< The device has been disconnected
#define POLLNVAL 0x4000 ///< The specified file handle value is invalid
namespace mbed {
class FileHandle;
/** \addtogroup platform-public-api */
/** @{*/
/**
* \defgroup platform_poll poll functions
* @{
*/
struct pollfh {
FileHandle *fh;
short events;
short revents;
};
/** A mechanism to multiplex input/output over a set of file handles(file descriptors).
* For every file handle provided, poll() examines it for any events registered for that particular
* file handle.
*
* @param fhs an array of PollFh struct carrying a FileHandle and bitmasks of events
* @param nfhs number of file handles
* @param timeout timer value to timeout or -1 for loop forever
*
* @return number of file handles selected (for which revents is non-zero). 0 if timed out with nothing selected. -1 for error.
*/
int poll(pollfh fhs[], unsigned nfhs, int timeout);
/**@}*/
/**@}*/
} // namespace mbed
#endif //MBED_POLL_H