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///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2005, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
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///////////////////////////////////////////////////////////////////////////
#ifndef INCLUDED_IMF_THREADING_H
#define INCLUDED_IMF_THREADING_H
#include "ImfExport.h"
#include "ImfNamespace.h"
//-----------------------------------------------------------------------------
//
// Threading support for the IlmImf library
//
// The IlmImf library uses threads to perform reading and writing
// of OpenEXR files in parallel. The thread that calls the library
// always performs the actual file IO (this is usually the main
// application thread) whereas a several worker threads perform
// data compression and decompression. The number of worker
// threads can be any non-negative value (a value of zero reverts
// to single-threaded operation). As long as there is at least
// one worker thread, file IO and compression can potentially be
// done concurrently through pinelining. If there are two or more
// worker threads, then pipelining as well as concurrent compression
// of multiple blocks can be performed.
//
// Threading in the Imf library is controllable at two granularities:
//
// * The functions in this file query and control the total number
// of worker threads, which will be created globally for the whole
// library. Regardless of how many input or output files are
// opened simultaneously, the library will use at most this number
// of worker threads to perform all work. The default number of
// global worker threads is zero (i.e. single-threaded operation;
// everything happens in the thread that calls the library).
//
// * Furthermore, it is possible to set the number of threads that
// each input or output file should keep busy. This number can
// be explicitly set for each file. The default behavior is for
// each file to try to occupy all worker threads in the library's
// thread pool.
//
//-----------------------------------------------------------------------------
OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER
//-----------------------------------------------------------------------------
// Return the number of Imf-global worker threads used for parallel
// compression and decompression of OpenEXR files.
//-----------------------------------------------------------------------------
IMF_EXPORT int globalThreadCount ();
//-----------------------------------------------------------------------------
// Change the number of Imf-global worker threads
//-----------------------------------------------------------------------------
IMF_EXPORT void setGlobalThreadCount (int count);
OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT
#endif
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