gdb/ser-event.h

   1 /* Serial interface for a selectable event.
   2    Copyright (C) 2016-2020 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