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authorDavid Robillard <d@drobilla.net>2007-07-24 19:26:47 +0000
committerDavid Robillard <d@drobilla.net>2007-07-24 19:26:47 +0000
commit3b4a308ff647def75e647ac8f97e1e48b57672c3 (patch)
treea33e3a5c78f2ee7f23e151f39fe17ab39b0b81c8 /raul/Semaphore.hpp
parentfcb302e6248527b2f1fb655f4d0a64af18f5f059 (diff)
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Consistently rename all C++ files .cpp/.hpp.
Fix (some) inclusion guard names to not clash with other libs. git-svn-id: http://svn.drobilla.net/lad/raul@613 a436a847-0d15-0410-975c-d299462d15a1
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+/* This file is part of Raul.
+ * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
+ *
+ * Raul 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 2 of the License, or (at your option) any later
+ * version.
+ *
+ * Raul 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 details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef RAUL_SEMAPHORE_HPP
+#define RAUL_SEMAPHORE_HPP
+
+#include <semaphore.h>
+#include <boost/utility.hpp>
+
+namespace Raul {
+
+
+/** Trivial wrapper around POSIX semaphores (zero memory overhead).
+ *
+ * This was created to provide an alternative debuggable implementation of
+ * semaphores based on a cond/mutex pair because semaphore's appeared not to
+ * work in GDB. Turns out sem_wait can fail when run in GDB, and Debian
+ * really needs to update it's man pages.
+ *
+ * This class remains as a trivial (yet pretty) wrapper/abstraction.
+ *
+ * \ingroup raul
+ */
+class Semaphore : boost::noncopyable {
+public:
+ inline Semaphore(unsigned int initial) { sem_init(&_sem, 0, initial); }
+
+ inline ~Semaphore() { sem_destroy(&_sem); }
+
+ inline void reset(unsigned int initial)
+ { sem_destroy(&_sem); sem_init(&_sem, 0, initial); }
+
+ /** Increment (and signal any waiters).
+ *
+ * Realtime safe.
+ */
+ inline void post() { sem_post(&_sem); }
+
+ /** Wait until count is > 0, then decrement.
+ *
+ * Note that sem_wait always returns 0 in practise. It returns nonzero
+ * when run in GDB, so the while is necessary to allow debugging.
+ *
+ * Obviously not realtime safe.
+ */
+ inline void wait() { while (sem_wait(&_sem) != 0) ; }
+
+ /** Non-blocking version of wait().
+ *
+ * Realtime safe?
+ */
+ inline int try_wait() { return sem_trywait(&_sem); }
+
+private:
+ sem_t _sem;
+};
+
+
+} // namespace Raul
+
+#endif // RAUL_SEMAPHORE_HPP