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mbed_poll.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2017-2019 ARM Limited
3  * SPDX-License-Identifier: Apache-2.0
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 #ifndef MBED_POLL_H
18 #define MBED_POLL_H
19 
20 #define POLLIN 0x0001 ///< Data may be read without blocking
21 #define POLLOUT 0x0010 ///< Data may be written without blocking
22 #define POLLERR 0x1000 ///< An error has occurred on the device or stream
23 #define POLLHUP 0x2000 ///< The device has been disconnected
24 #define POLLNVAL 0x4000 ///< The specified file handle value is invalid
25 
26 namespace mbed {
27 
28 class FileHandle;
29 
30 /** \addtogroup platform-public-api */
31 /** @{*/
32 
33 /**
34  * \defgroup platform_poll poll functions
35  * @{
36  */
37 
38 struct pollfh {
39  FileHandle *fh;
40  short events;
41  short revents;
42 };
43 
44 /** A mechanism to multiplex input/output over a set of file handles(file descriptors).
45  * For every file handle provided, poll() examines it for any events registered for that particular
46  * file handle.
47  *
48  * @param fhs an array of PollFh struct carrying a FileHandle and bitmasks of events
49  * @param nfhs number of file handles
50  * @param timeout timer value to timeout or -1 for loop forever
51  *
52  * @return number of file handles selected (for which revents is non-zero). 0 if timed out with nothing selected. -1 for error.
53  */
54 int poll(pollfh fhs[], unsigned nfhs, int timeout);
55 
56 /**@}*/
57 
58 /**@}*/
59 
60 } // namespace mbed
61 
62 #endif //MBED_POLL_H
mbed::poll
int poll(pollfh fhs[], unsigned nfhs, int timeout)
A mechanism to multiplex input/output over a set of file handles(file descriptors).
mbed::FileHandle
Class FileHandle.
Definition: FileHandle.h:46
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