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|   | ParallelOptions Class Reference |  | 
Option base class for parallel algorithms. More...
#include <vigra/threadpool.hxx>
 
  
 | Public Types | |
| enum | { Auto = -1, Nice = -2, NoThreads = 0 } | 
| Public Member Functions | |
| int | getActualNumThreads () const | 
| Get desired number of threads.  More... | |
| int | getNumThreads () const | 
| Get desired number of threads.  More... | |
| ParallelOptions & | numThreads (const int n) | 
| Set the number of threads or one of the constants Auto,NiceandNoThreads.  More... | |
Option base class for parallel algorithms.
#include <vigra/threadpool.hxx>
 Namespace: vigra 
| anonymous enum | 
| int getNumThreads | ( | ) | const | 
Get desired number of threads.
Note: This function may return 0, which means that multi-threading shall be switched off entirely. If an algorithm receives this value, it should revert to a sequential implementation. In contrast, if numThread() == 1, the parallel algorithm version shall be executed with a single thread. 
| int getActualNumThreads | ( | ) | const | 
Get desired number of threads.
In contrast to numThread(), this will always return a value >=1. 
| ParallelOptions& numThreads | ( | const int | n | ) | 
Set the number of threads or one of the constants Auto, Nice and NoThreads. 
Default: ParallelOptions::Auto (use system default)
This setting is ignored if the preprocessor flag VIGRA_SINGLE_THREADED is defined. Then, the number of threads is set to 0 and all tasks revert to sequential algorithm implementations. The same can be achieved at runtime by passing n = 0 to this function. In contrast, passing n = 1 causes the parallel algorithm versions to be executed with a single thread. Both possibilities are mainly useful for debugging. 
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© Ullrich Köthe     (ullrich.koethe@iwr.uni-heidelberg.de)  | 
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