bitcoin/src/shutdown.h
Wladimir J. van der Laan cd03513dc2 init: Signal-safe instant shutdown
Replace the 200ms polling loop with a faster and more efficient waiting
operation.

This was tried a few times before, but given up every time because
solutions use a condition variable which is not safe for use in signals
as they need to be reentrant.

On UNIX-ish OSes, use a safe way: a pipe. When shutdown is requested
write a dummy byte to the pipe. Waiting for shutdown is a matter of a
blocking read from the pipe.

On Windows, there are no signals so using a condition variable is safe.
2020-12-15 17:21:06 +01:00

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1,009 B
C

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_SHUTDOWN_H
#define BITCOIN_SHUTDOWN_H
/** Initialize shutdown state. This must be called before using either StartShutdown(),
* AbortShutdown() or WaitForShutdown(). Calling ShutdownRequested() is always safe.
*/
bool InitShutdownState();
/** Request shutdown of the application. */
void StartShutdown();
/** Clear shutdown flag. Only use this during init (before calling WaitForShutdown in any
* thread), or in the unit tests. Calling it in other circumstances will cause a race condition.
*/
void AbortShutdown();
/** Returns true if a shutdown is requested, false otherwise. */
bool ShutdownRequested();
/** Wait for StartShutdown to be called in any thread. This can only be used
* from a single thread.
*/
void WaitForShutdown();
#endif