+
−/* Non-blocking I/O for pipe or socket descriptors.
+
−   Copyright (C) 2011-2012 Free Software Foundation, Inc.
+
−
+
−   This program is free software: you can redistribute it and/or modify
+
−   it under the terms of the GNU General Public License as published by
+
−   the Free Software Foundation; either version 3 of the License, or
+
−   (at your option) any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
+
−   but WITHOUT ANY WARRANTY; without even the implied warranty of
+
−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+
−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
−
+
−#ifndef _NONBLOCKING_H
+
−#define _NONBLOCKING_H
+
−
+
−#include <stdbool.h>
+
−
+
−/* Non-blocking I/O is an I/O mode by which read(), write() calls avoid
+
−   blocking the current thread.  When non-blocking is enabled:
+
−   - A read() call returns -1 with errno set to EAGAIN when no data or EOF
+
−     information is immediately available.
+
−   - A write() call returns -1 with errno set to EAGAIN when it cannot
+
−     transport the requested amount of data (but at most one pipe buffer)
+
−     without blocking.
+
−   Non-blocking I/O is most useful for character devices, pipes, and sockets.
+
−   Whether it also works on regular files and block devices is platform
+
−   dependent.
+
−
+
−   There are three modern alternatives to non-blocking I/O:
+
−     - use select() or poll() followed by read() or write() if the descriptor
+
−       is ready,
+
−     - call read() or write() in separate threads,
+
−     - use <aio.h> interfaces.  */
+
−
+
−
+
−#ifdef __cplusplus
+
−extern "C" {
+
−#endif
+
−
+
−
+
−/* Return 1 if I/O to the descriptor DESC is currently non-blocking, 0
+
−   it is blocking, or -1 with errno set if fd is invalid or blocking
+
−   status cannot be determined (such as with sockets on mingw).  */
+
−extern int get_nonblocking_flag (int desc);
+
−
+
−/* Specify the non-blocking flag for the descriptor DESC.
+
−   Return 0 upon success, or -1 with errno set upon failure.
+
−   The default depends on the presence of the O_NONBLOCK flag for files
+
−   or pipes opened with open() or on the presence of the SOCK_NONBLOCK
+
−   flag for sockets.  */
+
−extern int set_nonblocking_flag (int desc, bool value);
+
−
+
−
+
−#ifdef __cplusplus
+
−}
+
−#endif
+
−
+
−#endif /* _NONBLOCKING_H */