Recent changes to Code examples

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Tue, 08 Oct 2019 12:47:27 -0000

--- v7
+++ v8
@@ -216,22 +216,21 @@
 ~~~

 The output may look like
-~~~
-Put 0
-Get 0
-Put 1
-Get 1
-Put 2
-Get 2
-Put 3
-Get 3
-Put 4
-Get 4
-Put 5
-Put 6
-Put 7
-Put 8
-Call condition (errno = pthread_cancel(m_handle)) == 0 at ../src/posix_threads_thread.cpp:134 Unable to cancel thread: No such process
-~~~
+> Put 0
+> Get 0
+> Put 1
+> Get 1
+> Put 2
+> Get 2
+> Put 3
+> Get 3
+> Put 4
+> Get 4
+> Put 5
+> Put 6
+> Put 7
+> Put 8
+> Call condition (errno = pthread_cancel(m_handle)) == 0 at ../src/posix_threads_thread.cpp:134 Unable to cancel thread: No such process
+
 The Reader thread  has no delay in it's loop, but blocks on the queue empty condition every time it gets the last element of the queue.
 The writer thread blocks after inserting 8th element, because reader takes only 5 elements (0-4) and the queue has only 4 elements capacity.

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Tue, 08 Oct 2019 12:45:47 -0000

--- v6
+++ v7
@@ -213,5 +213,25 @@

    return EXIT_SUCCESS;
 }
-
-~~~
+~~~
+
+The output may look like
+~~~
+Put 0
+Get 0
+Put 1
+Get 1
+Put 2
+Get 2
+Put 3
+Get 3
+Put 4
+Get 4
+Put 5
+Put 6
+Put 7
+Put 8
+Call condition (errno = pthread_cancel(m_handle)) == 0 at ../src/posix_threads_thread.cpp:134 Unable to cancel thread: No such process
+~~~
+The Reader thread  has no delay in it's loop, but blocks on the queue empty condition every time it gets the last element of the queue.
+The writer thread blocks after inserting 8th element, because reader takes only 5 elements (0-4) and the queue has only 4 elements capacity.

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Tue, 08 Oct 2019 12:41:38 -0000

--- v5
+++ v6
@@ -45,7 +45,7 @@

 ## 2.1 Bounded synchronous queue ##

-~~~
+~~~C++
 #include <cstdlib>

 #include <iostream>
</iostream></cstdlib>

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Tue, 08 Oct 2019 12:41:13 -0000

--- v4
+++ v5
@@ -1,6 +1,6 @@
 # 1. Asynchronous function call #

-~~~
+~~~C++

 #include <cstdlib>

</cstdlib>

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Tue, 08 Oct 2019 12:37:12 -0000

--- v3
+++ v4
@@ -44,3 +44,174 @@
 # 2. Synchronization primitives #

 ## 2.1 Bounded synchronous queue ##
+
+~~~
+#include <cstdlib>
+
+#include <iostream>
+#include <queue>
+
+#include "posix_threads_thread.hpp"
+#include "posix_threads_mutex.hpp"
+#include "posix_threads_condition.hpp"
+#include "posix_threads_criticalsection.hpp"
+
+template <typename t="">
+class BoundedSyncBlockingQueue
+{
+public:
+   
+   explicit BoundedSyncBlockingQueue(size_t capaciy) :
+   m_fullCond(m_lock),
+   m_emptyCond(m_lock),
+   m_capacity(capaciy)
+   {
+   }
+   
+   void enqueue(const T& item)
+   {
+       posix::threads::CriticalSection cs(m_lock);
+       
+       while (m_baseQueue.size() >= m_capacity)
+           m_fullCond.wait();
+       
+       m_baseQueue.push(item);
+       
+       if (m_baseQueue.size() == 1)
+           m_emptyCond.broadcast();
+   }
+   
+   T dequeue()
+   {
+       posix::threads::CriticalSection cs(m_lock);
+       
+       while (m_baseQueue.empty())
+           m_emptyCond.wait();
+       
+       T result = m_baseQueue.front();
+       m_baseQueue.pop();
+       
+       if (m_baseQueue.size() == (m_capacity - 1))
+           m_fullCond.broadcast();
+       
+       return result;
+   }
+   
+   size_t getSize() const
+   {
+       posix::threads::CriticalSection cs(m_lock);
+       
+       return m_baseQueue.size();
+   }
+   
+private :
+   
+   mutable posix::threads::Mutex m_lock;
+   
+   posix::threads::Condition m_fullCond;
+   
+   posix::threads::Condition m_emptyCond;
+   
+   const size_t m_capacity;
+   
+   std::queue<t> m_baseQueue;
+};
+
+static posix::threads::Mutex stdoutLock;
+
+class Reader : public posix::threads::Thread
+{
+public:
+   
+   explicit Reader(BoundedSyncBlockingQueue<int>& q) :
+   m_queue(q)
+   {
+   }
+   
+private:
+   
+   BoundedSyncBlockingQueue<int>& m_queue;
+   
+// posixcpp::ActiveObjectInterface
+public:
+   
+   void run() override
+   {
+       for (uint8_t i=0; i<5; ++i) {
+           int a = m_queue.dequeue();
+           stdoutLock.lock();
+           std::cout << "Get " << int(a) << std::endl;
+           stdoutLock.unlock();
+       }
+   }
+};
+
+class Writer : public posix::threads::Thread
+{
+public:
+   
+   explicit Writer(BoundedSyncBlockingQueue<int>& q) :
+   m_queue(q)
+   {
+   }
+   
+private:
+   
+   BoundedSyncBlockingQueue<int>& m_queue;
+   
+// posixcpp::ActiveObjectInterface
+public:
+   
+   void run() override
+   {
+       for (uint8_t i=0; i<10; ++i) {
+           posix::time::sleep(1);
+           m_queue.enqueue(int(i));
+           stdoutLock.lock();
+           std::cout << "Put " << int(i) << std::endl;
+           stdoutLock.unlock();
+       }
+   }
+};
+
+int
+main(int argc, char** argv)
+{
+   BoundedSyncBlockingQueue<int> queue(4);
+   
+   Reader r(queue);
+   Writer w(queue);
+   
+   r.start();
+   w.start();
+   
+   posix::time::sleep(11);
+   
+   try {
+       r.cancel();
+   } catch (const std::exception& ex) {
+       std::cerr << ex.what() << std::endl;
+   }
+   
+   try {
+       w.cancel();
+   } catch (const std::exception& ex) {
+       std::cerr << ex.what() << std::endl;
+   }
+   
+   try {
+       r.join();
+   } catch (const std::exception& ex) {
+       std::cerr << ex.what() << std::endl;
+   }
+   
+   try {
+       w.join();
+   } catch (const std::exception& ex) {
+       std::cerr << ex.what() << std::endl;
+   }
+   
+   return EXIT_SUCCESS;
+}
+
+~~~
</int></int></int></int></int></t></typename></queue></iostream></cstdlib>

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Thu, 03 Oct 2019 13:33:36 -0000

--- v2
+++ v3
@@ -1,10 +1,45 @@
 # 1. Asynchronous function call #

-## 1.1 Thread ##
+~~~

+#include <cstdlib>

+#include <iostream>
+#include <memory>

-## 1.2 Process ##
+#include "posix_threads_thread.hpp"
+#include "posix_process.hpp"
+
+void* asyncFunction(void* param)
+{
+   std::cout << __PRETTY_FUNCTION__ << std::endl;
+}
+
+#define PROCESS 0
+#define THREAD 1
+
+//#define MODE PROCESS
+#define MODE THREAD
+
+int
+main(int argc, char** argv)
+{
+   std::unique_ptr<posixcpp::activeobject> activeObject;
+#if MODE == PROCESS
+   activeObject.reset(new posix::Process(asyncFunction));
+#else
+   activeObject.reset(new posix::threads::Thread(asyncFunction));
+#endif
+   
+   activeObject->start();
+   activeObject->waitFinish();
+   
+   std::cout << "Complete" << std::endl;
+   
+   return EXIT_SUCCESS;
+}
+
+~~~

 # 2. Synchronization primitives #

</posixcpp::activeobject></memory></iostream></cstdlib>

Code examples modified by Andrey Skvortsov

Andrey Skvortsov — Thu, 03 Oct 2019 13:25:49 -0000

--- v1
+++ v2
@@ -1,8 +1,11 @@
-Welcome to your wiki!
+# 1. Asynchronous function call #

-This is the default page, edit it as you see fit. To add a new page simply reference it within brackets, e.g.: [SamplePage].
+## 1.1 Thread ##

-The wiki uses [Markdown](/p/posixcpp/wiki/markdown_syntax/) syntax.

-[[members limit=20]]
-[[download_button]]
+
+## 1.2 Process ##
+
+# 2. Synchronization primitives #
+
+## 2.1 Bounded synchronous queue ##

Home modified by Andrey Skvortsov

Andrey Skvortsov — Wed, 02 Oct 2019 07:48:45 -0000

Welcome to your wiki!

This is the default page, edit it as you see fit. To add a new page simply reference it within brackets, e.g.: [SamplePage].

The wiki uses Markdown syntax.

Project Members:

Andrey Skvortsov (admin)