/src/FreeImage/Source/OpenEXR/IlmImf/ImfThreading.h

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34
35#ifndef INCLUDED_IMF_THREADING_H
36#define INCLUDED_IMF_THREADING_H
37
38//-----------------------------------------------------------------------------
39//
40//	Threading support for the IlmImf library
41//
42//	The IlmImf library uses threads to perform reading and writing
43//	of OpenEXR files in parallel.  The thread that calls the library
44//	always performs the actual file IO (this is usually the main
45//	application thread) whereas a several worker threads perform
46//	data compression and decompression.  The number of worker
47//	threads can be any non-negative value (a value of zero reverts
48//	to single-threaded operation).  As long as there is at least
49//	one worker thread, file IO and compression can potentially be
50//	done concurrently through pinelining.  If there are two or more
51//	worker threads, then pipelining as well as concurrent compression
52//	of multiple blocks can be performed.
53// 
54//	Threading in the Imf library is controllable at two granularities:
55//
56//	* The functions in this file query and control the total number
57//	  of worker threads, which will be created globally for the whole
58//	  library.  Regardless of how many input or output files are
59//	  opened simultaneously, the library will use at most this number
60//	  of worker threads to perform all work.  The default number of
61//	  global worker threads is zero (i.e. single-threaded operation;
62//	  everything happens in the thread that calls the library).
63//
64//	* Furthermore, it is possible to set the number of threads that
65//	  each input or output file should keep busy.  This number can
66//	  be explicitly set for each file.  The default behavior is for
67//	  each file to try to occupy all worker threads in the library's
68//	  thread pool.
69//
70//-----------------------------------------------------------------------------
71
72namespace Imf {
73
74
75//-----------------------------------------------------------------------------
76// Return the number of Imf-global worker threads used for parallel
77// compression and decompression of OpenEXR files.
78//-----------------------------------------------------------------------------
79    
80int     globalThreadCount ();
81
82
83//-----------------------------------------------------------------------------
84// Change the number of Imf-global worker threads
85//-----------------------------------------------------------------------------
86
87void    setGlobalThreadCount (int count);
88
89
90} // namespace Imf
91
92#endif