1 /* Serial interface for a selectable event. 2 Copyright (C) 2016-2019 Free Software Foundation, Inc. 3 4 This file is part of GDB. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 18 19 #ifndef SER_EVENT_H 20 #define SER_EVENT_H 21 22 /* This is used to be able to signal the event loop (or any other 23 select/poll) of events, in a race-free manner. 24 25 For example, a signal handler can defer non-async-signal-safe work 26 to the event loop, by having the signal handler set a struct 27 serial_event object, and having the event loop wait for that same 28 object to the readable. Once readable, the event loop breaks out 29 of select/poll and calls a registered callback that does the 30 deferred work. */ 31 32 struct serial_event; 33 34 /* Make a new serial_event object. */ 35 struct serial_event *make_serial_event (void); 36 37 /* Return the FD that can be used by select/poll to wait for the 38 event. The only valid operation on this object is to wait until it 39 is readable. */ 40 extern int serial_event_fd (struct serial_event *event); 41 42 /* Set the event. This signals the file descriptor returned by 43 serial_event_fd as readable. */ 44 extern void serial_event_set (struct serial_event *event); 45 46 /* Clear the event. The file descriptor returned by serial_event_fd 47 is not longer readable after this, until a new serial_event_set 48 call is made. */ 49 extern void serial_event_clear (struct serial_event *event); 50 51 #endif 52