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+/*
+ * The MIT License
+ *
+ * Copyright (C) 2010-2017 Alexander Saprykin <saprykin.spb@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * 'Software'), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * @file pmutex.h
+ * @brief Mutex routines
+ * @author Alexander Saprykin
+ *
+ * A mutex is a mutual exclusive (hence mutex) synchronization primitive which
+ * allows access to a critical section only to one of the concurrently running
+ * threads. It is used to protected shared data structures from concurrent
+ * modifications which could lead to unpredictable behavior.
+ *
+ * When entering a critical section a thread must call p_mutex_lock() to get a
+ * lock. If another thread is already holding the lock all other threads will
+ * be suspended until the lock is released with p_mutex_unlock(). After
+ * releasing the lock one of the waiting threads is resumed to continue
+ * execution. On most systems it is not specified whether a mutex waiting queue
+ * is fair (FIFO) or not.
+ *
+ * The typical mutex usage:
+ * @code
+ * p_mutex_lock (mutex);
+ *
+ * ... code in critical section ...
+ *
+ * p_mutex_unlock (mutex);
+ * @endcode
+ * You can also think of the mutex as a binary semaphore.
+ *
+ * It is implementation dependent whether recursive locking or non-locked mutex
+ * unlocking is allowed, but such actions can lead to unpredictable behavior.
+ * Do not rely on such behavior in cross-platform applications.
+ *
+ * This is the thread scoped mutex implementation. You could not share this
+ * mutex outside the process adress space, but you can share it between the
+ * threads of the same process.
+ */
+
+#if !defined (PLIBSYS_H_INSIDE) && !defined (PLIBSYS_COMPILATION)
+# error "Header files shouldn't be included directly, consider using <plibsys.h> instead."
+#endif
+
+#ifndef PLIBSYS_HEADER_PMUTEX_H
+#define PLIBSYS_HEADER_PMUTEX_H
+
+#include <pmacros.h>
+#include <ptypes.h>
+
+P_BEGIN_DECLS
+
+/** Mutex opaque data structure. */
+typedef struct PMutex_ PMutex;
+
+/**
+ * @brief Creates a new #PMutex object.
+ * @return Pointer to a newly created #PMutex object.
+ * @since 0.0.1
+ */
+P_LIB_API PMutex * p_mutex_new (void);
+
+/**
+ * @brief Locks a mutex.
+ * @param mutex #PMutex to lock.
+ * @return TRUE in case of success, FALSE otherwise.
+ * @since 0.0.1
+ * @warning Do not lock the mutex recursively - it may lead to an application
+ * deadlock (implementation dependent).
+ *
+ * Forces the calling thread to sleep until @a mutex becomes available for
+ * locking.
+ */
+P_LIB_API pboolean p_mutex_lock (PMutex *mutex);
+
+/**
+ * @brief Tries to lock a mutex immediately.
+ * @param mutex #PMutex to lock.
+ * @return TRUE in case of success, FALSE otherwise.
+ * @since 0.0.1
+ * @warning Do not lock the mutex recursively - it may lead to an application
+ * deadlock (implementation dependent).
+ *
+ * Tries to lock @a mutex and returns immediately if it is not available for
+ * locking.
+ */
+P_LIB_API pboolean p_mutex_trylock (PMutex *mutex);
+
+/**
+ * @brief Releases a locked mutex.
+ * @param mutex #PMutex to release.
+ * @return TRUE in case of success, FALSE otherwise.
+ * @since 0.0.1
+ * @warning Do not use this function on non-locked mutexes - behavior may be
+ * unpredictable.
+ *
+ * If @a mutex was previously locked then it becomes unlocked.
+ *
+ * It's implementation dependent whether only the same thread can lock and
+ * unlock the same mutex.
+ */
+P_LIB_API pboolean p_mutex_unlock (PMutex *mutex);
+
+/**
+ * @brief Frees #PMutex object.
+ * @param mutex #PMutex to free.
+ * @since 0.0.1
+ * @warning It doesn't unlock @a mutex before freeing memory, so you should do
+ * it manually.
+ */
+P_LIB_API void p_mutex_free (PMutex *mutex);
+
+P_END_DECLS
+
+#endif /* PLIBSYS_HEADER_PMUTEX_H */