diff --git a/libs/main/thread/pireadwritelock.cpp b/libs/main/thread/pireadwritelock.cpp
new file mode 100644
index 00000000..99ebb209
--- /dev/null
+++ b/libs/main/thread/pireadwritelock.cpp
@@ -0,0 +1,234 @@
+/*
+    PIP - Platform Independent Primitives
+	PIReadWriteLock, PIReadLocker, PIWriteLocker
+	Ivan Pelipenko peri4ko@yandex.ru
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+//! \addtogroup Thread
+//! \{
+//! \class PIReadWriteLock pireadwritelock.h
+//!
+//! \~\brief
+//! \~english Read/Write lock
+//! \~russian Блокировка чтения/записи
+//!
+//!
+//! \~\details
+//! \~english \section PIReadWriteLock_sec0 Synopsis
+//! \~russian \section PIReadWriteLock_sec0 Краткий обзор
+//!
+//! \~english
+//! %PIReadWriteLock provides more complex critical code section defence between several threads.
+//! %PIReadWriteLock permit only one thread to modify data, besides multiple thread can read data
+//! simultaneously. Conatains methods:
+//! \a lockWrite(), \a tryLockWrite(), \a unlockWrite(), \a lockRead(), \a tryLockRead() and \a unlockRead().
+//!
+//! For automatic read and write locks use \a PIReadLocker and \a PIWriteLocker.
+//!
+//! \~russian
+//! %PIReadWriteLock предоставляет более сложную межпотоковую защиту критических секций кода.
+//! %PIReadWriteLock разрешает только одному потоку изменять данные, в то время как читать данные
+//! могут одновременно несколько потоков.
+//! Содержит методы:
+//! \a lockWrite(), \a tryLockWrite(), \a unlockWrite(), \a lockRead(), \a tryLockRead() и \a unlockRead().
+//!
+//! Для автоматической блокировки на чтение и запись используйте \a PIReadLocker и \a PIWriteLocker.
+//!
+//! \~english \section PIReadWriteLock_sec1 Usage
+//! \~russian \section PIReadWriteLock_sec1 Использование
+//!
+//! \~english
+//! When one thread lock for write with \a lockWrite(), all other threads (read and write) can`t access data until this thread
+//! call \a unlockWrite(). In this way, write lock works similar to mutex.
+//!
+//! On the other hand, several threads can simultaneously read data. In other words, \a lockRead() increase read threads counter
+//! and \a unlockRead() decrease. But thread can`t read data while other thread locked for write.
+//!
+//! \~russian
+//! Когда один поток блокирует запись с помощью функции \a lockWrite(), все остальные потоки (чтение и запись) не смогут получить
+//! доступ к данным, пока этот поток не вызовет \a unlockWrite(). Таким образом, блокировка записи работает аналогично мьютексу.
+//!
+//! С другой стороны, несколько потоков могут одновременно считывать данные. Другими словами, функция \a lockRead() увеличивает счетчик
+//! потоков чтения, а функция \a unlockRead() уменьшает. Но поток не может считывать данные, пока другой поток заблокирован для записи.
+//!
+//! \~\code
+//! \endcode
+//! \}
+
+
+//! \addtogroup Thread
+//! \{
+//! \class PIReadLocker pireadwritelock.h
+//!
+//! \~\brief
+//! \~english %PIReadWriteLock read autolocker
+//! \~russian Автоблокировщик на чтение %PIReadWriteLock
+//!
+//!
+//! \~\details
+//!
+//! \~english
+//! When a %PIReadLocker object is created, it lock %PIReadWriteLock for read, if "condition" \c true.
+//! When control leaves the scope in which the %PIReadLocker object was created,
+//! the %PIReadLocker is destructed and unlock for read, if "condition" was \c true.
+//!
+//! If "condition" \c false this class do nothing.
+//!
+//! The %PIReadLocker class is non-copyable.
+//!
+//! \~russian
+//! При создании экземпляра %PIReadLocker он блокирует %PIReadWriteLock на чтение, если "condition" \c true.
+//! Когда выполнение покидает область жизни объекта, вызывается его деструктор и освобождается блокировка на чтение,
+//! если "condition" был \c true.
+//!
+//! Если "condition" \c false, то этот объект ничего не делает.
+//!
+//! Класс %PIReadLocker некопируемый.
+//!
+//! \~\code
+//! // critical section start
+//! {
+//! PIReadLocker locker(rw_lock);
+//! // ... your read code here
+//! }
+//! // critical section end
+//! \endcode
+//! \}
+
+
+//! \addtogroup Thread
+//! \{
+//! \class PIWriteLocker pireadwritelock.h
+//!
+//! \~\brief
+//! \~english %PIReadWriteLock write autolocker
+//! \~russian Автоблокировщик на запись %PIReadWriteLock
+//!
+//!
+//! \~\details
+//!
+//! \~english
+//! When a %PIWriteLocker object is created, it lock %PIReadWriteLock for write, if "condition" \c true.
+//! When control leaves the scope in which the %PIWriteLocker object was created,
+//! the %PIWriteLocker is destructed and unlock for write, if "condition" was \c true.
+//!
+//! If "condition" \c false this class do nothing.
+//!
+//! The %PIWriteLocker class is non-copyable.
+//!
+//! \~russian
+//! При создании экземпляра %PIWriteLocker он блокирует %PIReadWriteLock на запись, если "condition" \c true.
+//! Когда выполнение покидает область жизни объекта, вызывается его деструктор и освобождается блокировка на запись,
+//! если "condition" был \c true.
+//!
+//! Если "condition" \c false, то этот объект ничего не делает.
+//!
+//! Класс %PIWriteLocker некопируемый.
+//!
+//! \~\code
+//! // critical section start
+//! {
+//! PIWriteLocker locker(rw_lock);
+//! // ... your write code here
+//! }
+//! // critical section end
+//! \endcode
+//! \}
+
+
+#include "pireadwritelock.h"
+
+
+PIReadWriteLock::PIReadWriteLock() {}
+
+
+PIReadWriteLock::~PIReadWriteLock() {
+	var.notifyAll();
+}
+
+
+void PIReadWriteLock::lockWrite() {
+	PIMutexLocker _ml(mutex);
+	while (reading > 0 || writing) {
+		var.wait(mutex);
+	}
+	writing = true;
+}
+
+
+bool PIReadWriteLock::tryLockWrite() {
+	PIMutexLocker _ml(mutex);
+	if (reading > 0 || writing) return false;
+	writing = true;
+	return true;
+}
+
+
+bool PIReadWriteLock::tryLockWrite(PISystemTime timeout) {
+	PITimeMeasurer tm;
+	PIMutexLocker _ml(mutex);
+	while (reading > 0 || writing) {
+		PISystemTime remain = timeout - tm.elapsed();
+		if (remain.isNegative()) return false;
+		var.waitFor(mutex, remain);
+	}
+	writing = true;
+	return true;
+}
+
+
+void PIReadWriteLock::unlockWrite() {
+	PIMutexLocker _ml(mutex);
+	writing = false;
+	var.notifyAll();
+}
+
+
+void PIReadWriteLock::lockRead() {
+	PIMutexLocker _ml(mutex);
+	while (writing) {
+		var.wait(mutex);
+	}
+	++reading;
+}
+
+
+bool PIReadWriteLock::tryLockRead() {
+	PIMutexLocker _ml(mutex);
+	if (writing) return false;
+	++reading;
+	return true;
+}
+
+
+bool PIReadWriteLock::tryLockRead(PISystemTime timeout) {
+	PITimeMeasurer tm;
+	PIMutexLocker _ml(mutex);
+	while (writing) {
+		PISystemTime remain = timeout - tm.elapsed();
+		if (remain.isNegative()) return false;
+		var.waitFor(mutex, remain);
+	}
+	++reading;
+	return true;
+}
+
+
+void PIReadWriteLock::unlockRead() {
+	PIMutexLocker _ml(mutex);
+	--reading;
+	var.notifyAll();
+}
diff --git a/libs/main/thread/pireadwritelock.h b/libs/main/thread/pireadwritelock.h
new file mode 100644
index 00000000..24b08a37
--- /dev/null
+++ b/libs/main/thread/pireadwritelock.h
@@ -0,0 +1,130 @@
+/*! \file pireadwritelock.h
+ * \ingroup Read/Write lock
+ * \~\brief
+ * \~english Read/Write lock
+ * \~russian Блокировка чтения/записи
+ */
+/*
+    PIP - Platform Independent Primitives
+	PIReadWriteLock, PIReadLocker, PIWriteLocker
+	Ivan Pelipenko peri4ko@yandex.ru
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef PIREADWRITELOCK_H
+#define PIREADWRITELOCK_H
+
+#include "piconditionvar.h"
+
+
+class PIP_EXPORT PIReadWriteLock {
+public:
+	NO_COPY_CLASS(PIReadWriteLock)
+
+	//! \~english Constructs %PIReadWriteLock.
+	//! \~russian Создает %PIReadWriteLock.
+	PIReadWriteLock();
+
+	//! \~english Destroy %PIReadWriteLock.
+	//! \~russian Деструктор %PIReadWriteLock.
+	~PIReadWriteLock();
+
+
+	//! \~english Lock for write. If already locked for write or read, than wait until all locks released.
+	//! \~russian Заблокировать на запись. Если уже заблокировано на запись или чтение, то ждёт освобождения блокировок.
+	void lockWrite();
+
+	//! \~english Try to lock for write. Returns if operation was successfull.
+	//! \~russian Пробует заблокировать на запись. Возвращает успех операции.
+	bool tryLockWrite();
+
+	//! \~english Try to lock for write for \"timeout\". Returns if operation was successfull (timeout has not expired).
+	//! \~russian Пробует заблокировать на запись в течении \"timeout\". Возвращает успех операции (не истек ли тайм-аут).
+	bool tryLockWrite(PISystemTime timeout);
+
+	//! \~english Release lock for write.
+	//! \~russian Освобождает блокировку на запись.
+	void unlockWrite();
+
+
+	//! \~english Lock for read. If already locked for write, than wait until write lock released.
+	//! \~russian Заблокировать на чтение. Если уже заблокировано на запись, то ждёт освобождения записывающей блокировки.
+	void lockRead();
+
+	//! \~english Try to lock for read. Returns if operation was successfull.
+	//! \~russian Пробует заблокировать на чтение. Возвращает успех операции.
+	bool tryLockRead();
+
+	//! \~english Try to lock for read for \"timeout\". Returns if operation was successfull (timeout has not expired).
+	//! \~russian Пробует заблокировать на чтение в течении \"timeout\". Возвращает успех операции (не истек ли тайм-аут).
+	bool tryLockRead(PISystemTime timeout);
+
+	//! \~english Release lock for read.
+	//! \~russian Освобождает блокировку на чтение.
+	void unlockRead();
+
+private:
+	int reading  = 0;
+	bool writing = false;
+	PIMutex mutex;
+	PIConditionVariable var;
+};
+
+
+class PIP_EXPORT PIReadLocker {
+public:
+	NO_COPY_CLASS(PIReadLocker);
+
+	//! \~english Constructs and lock for read %PIReadWriteLock "l" if "condition" is \c true.
+	//! \~russian Создается и блокирует на чтение %PIReadWriteLock "l" если "condition" \c true.
+	PIReadLocker(PIReadWriteLock & l, bool condition = true): rwl(l), cond(condition) {
+		if (cond) rwl.lockRead();
+	}
+
+	//! \~english Release read lock on %PIReadWriteLock if "condition" was \c true.
+	//! \~russian Освобождает блокировку на чтение %PIReadWriteLock если "condition" был \c true.
+	~PIReadLocker() {
+		if (cond) rwl.unlockRead();
+	}
+
+private:
+	PIReadWriteLock & rwl;
+	bool cond = true;
+};
+
+
+class PIP_EXPORT PIWriteLocker {
+public:
+	NO_COPY_CLASS(PIWriteLocker);
+
+	//! \~english Constructs and lock for write %PIReadWriteLock "l" if "condition" is \c true.
+	//! \~russian Создается и блокирует на запись %PIReadWriteLock "l" если "condition" \c true.
+	PIWriteLocker(PIReadWriteLock & l, bool condition = true): rwl(l), cond(condition) {
+		if (cond) rwl.lockWrite();
+	}
+
+	//! \~english Release write lock on %PIReadWriteLock if "condition" was \c true.
+	//! \~russian Освобождает блокировку на запись %PIReadWriteLock если "condition" был \c true.
+	~PIWriteLocker() {
+		if (cond) rwl.unlockWrite();
+	}
+
+private:
+	PIReadWriteLock & rwl;
+	bool cond = true;
+};
+
+
+#endif
diff --git a/libs/main/thread/pisemaphore.h b/libs/main/thread/pisemaphore.h
index 5f964408..7bacbecc 100644
--- a/libs/main/thread/pisemaphore.h
+++ b/libs/main/thread/pisemaphore.h
@@ -92,4 +92,4 @@ private:
 };
 
 
-#endif // PIMUTEX_H
+#endif
diff --git a/libs/main/thread/pithreadmodule.h b/libs/main/thread/pithreadmodule.h
index f5e7c7e3..eba1b509 100644
--- a/libs/main/thread/pithreadmodule.h
+++ b/libs/main/thread/pithreadmodule.h
@@ -56,6 +56,7 @@
 #include "pimutex.h"
 #include "pipipelinethread.h"
 #include "piprotectedvariable.h"
+#include "pireadwritelock.h"
 #include "pisemaphore.h"
 #include "pispinlock.h"
 #include "pithread.h"
diff --git a/main.cpp b/main.cpp
index 34c01013..338791b2 100644
--- a/main.cpp
+++ b/main.cpp
@@ -39,28 +39,66 @@ public:
 
 class RWL {
 public:
-	void lockWrite() { mutex.lock(); }
-	void unlockWrite() { mutex.unlock(); }
-	void lockRead() {}
-	void unlockRead() {}
+	void lockWrite() {
+		PIMutexLocker _ml(mutex);
+		while (reading > 0 || writing) {
+			var.wait(mutex);
+		}
+		writing = true;
+	}
+	void unlockWrite() {
+		PIMutexLocker _ml(mutex);
+		writing = false;
+		var.notifyAll();
+	}
+	void lockRead() {
+		PIMutexLocker _ml(mutex);
+		while (writing) {
+			var.wait(mutex);
+		}
+		++reading;
+	}
+	void unlockRead() {
+		PIMutexLocker _ml(mutex);
+		--reading;
+		var.notifyAll();
+	}
+
+private:
+	PIConditionVariable var;
+	int reading  = 0;
+	bool writing = false;
 	PIMutex mutex;
 };
 
 PIMutex mutex;
 PISemaphore sem(10);
+PIReadWriteLock rwl;
 
 int main(int argc, char * argv[]) {
 	/*sem.acquire(2);
 	piCout << sem.tryAcquire(2);
 	piCout << sem.available();
 	return 0;*/
-	PIThread t_w(
+	PIThread t_w0(
 		[] {
 			// PIMutexLocker _ml(mutex);
-			piCout << "write start ...";
+			PIWriteLocker rl(rwl);
+			piCout << "write0 start ...";
 			piMSleep(500);
-			sem.release(11);
-			piCout << "write end" << sem.available() << "\n";
+			piCout << "write0 end"
+				   << "\n";
+		},
+		true,
+		1_Hz);
+	PIThread t_w1(
+		[] {
+			// PIMutexLocker _ml(mutex);
+			PIWriteLocker rl(rwl);
+			piCout << "write1 start ...";
+			piMSleep(500);
+			piCout << "write1 end"
+				   << "\n";
 		},
 		true,
 		1_Hz);
@@ -69,33 +107,36 @@ int main(int argc, char * argv[]) {
 	PIThread t_r0(
 		[&cnt0] {
 			// PIMutexLocker _ml(mutex);
+			PIReadLocker rl(rwl);
 			piCout << "read0 start ...";
 			piMSleep(50);
-			sem.acquire(2);
-			bool ok = true; // sem.tryAcquire(2, 100_ms);
-			if (ok) ++cnt0;
-			piCout << "read0 end" << sem.available() << ok;
+			// bool ok = rwl.tryLockRead(100_ms);
+			// if (ok) ++cnt0;
+			piCout << "read0 end";
+			// if (ok) rwl.unlockRead();
 		},
 		true,
 		10_Hz);
 	PIThread t_r1(
 		[&cnt1] {
 			// PIMutexLocker _ml(mutex);
+			// PIReadLocker rl(rwl);
 			piCout << "read1 start ...";
 			piMSleep(50);
-			sem.acquire(2);
-			bool ok = true; // sem.tryAcquire(2, 100_ms);
+			bool ok = rwl.tryLockRead(100_ms);
 			if (ok) ++cnt1;
-			piCout << "read1 end" << sem.available() << ok;
+			piCout << "read1 end" << ok;
+			if (ok) rwl.unlockRead();
 		},
 		true,
 		11_Hz);
 
-	piSleep(5.);
+	piSleep(8.);
 
 	t_r0.stopAndWait();
 	t_r1.stopAndWait();
-	t_w.stopAndWait();
+	t_w0.stopAndWait();
+	t_w1.stopAndWait();
 
 	piCout << cnt0 << cnt1;