== Examples ==

=== Using task ===

From: https://software.intel.com/en-us/forums/intel-moderncode-for-parallel-architectures/topic/544780

{{{#!highlight c
struct Frame
{
  int bufferNumber; // 0, 1, ... nFrames-1
  uint8_t* buffer; // buffer[bufferSize];
  ...
  Frame(int n, size_t size)
  {
    bufferNumber = n;
    buffer = new uint8_t[size]; 
  }
  ~Frame() { if(buffer) delete [] buffer;
};

int nFrames = 0; // You determine number of buffers (should be > nThreads)
Frame* Frames = NULL; // [nFrames];
...
nFrames = omp_get_max_threads() + someMore;
Frames = new Frame*[nFrames];
for(int i=0; i < nFrames - 1; ++i)
  Frames[i] = new Frame(i, YourFrameSize);

volatile int frame_empty_index = 0;
volatile int frame_fill_index = 0;
#pragma omp parallel
{
  #pragma omp master
  {
    for(Frame* frame=get_next_frame(); frame;  frame=get_next_frame())
    {
      #pragma omp task
      {
         doWork(frame);
         while(frame->bufferNumber != frame_fill_index)
           Sleep(0); // release time slice
         write_frame(frame);
         frame_fill_index = (frame_fill_index + 1) % nFrames;
      }
    } // for
  } // master
}


//
Frame* get_next_frame()
{
   // wait for buffer
   while((frame_empty_index + 1) % nFrames == frame_fill_index)
     Sleep(0); // release time slice
   Frame* frame = frames[frame_empty_index];
   frame_empty_index = (frame_empty_index +1) % nFrameBuffers;
   read_frame(frame);
   return frame;
}
void write_frame(Frame* frame)
{
  while(frame->bufferNumber != frame_fill_index)
    Sleep(0);
  write(frame);
  frame_fill_index = (frame_fill_index + 1) % nFrames;
}

void doWork(Frame* frame)
{
...
}

}}}


Use of OpenMP in ImageMagick: https://github.com/ImageMagick/ImageMagick/search?utf8=%E2%9C%93&q=pragma+omp&type=Code

== Links ==

[[https://software.intel.com/en-us/articles/improve-performance-with-vectorization#footnote1|Improve Performance with Vectorization | Intel® Software]]

[[https://www.youtube.com/watch?v=o4UUnr8X8bI|Speed Up Image Processing with OpenMP - YouTube]]

[[http://bisqwit.iki.fi/story/howto/openmp/|Guide into OpenMP: Easy multithreading programming for C++]]

[[https://lists.blender.org/pipermail/bf-blender-cvs/2015-December/082469.html|[Bf-blender-cvs] [e6c6b5d] buildbot_linux_cmake: Buildbot: Link statically against gomp for CMake Linux slave]]: Linking libgomp (OpenMP runtime) statically w/ CMake/gcc