|
| Control.Concurrent.SampleVar | | Portability | non-portable (concurrency) | | Stability | experimental | | Maintainer | libraries@haskell.org |
|
|
|
|
|
| Description |
| Sample variables
|
|
| Synopsis |
|
|
|
|
| Sample Variables |
|
| type SampleVar a = MVar (Int, MVar a) |
Sample variables are slightly different from a normal MVar: Reading an empty SampleVar causes the reader to block.
(same as takeMVar on empty MVar) Reading a filled SampleVar empties it and returns value.
(same as takeMVar) Writing to an empty SampleVar fills it with a value, and
potentially, wakes up a blocked reader (same as for putMVar on
empty MVar). Writing to a filled SampleVar overwrites the current value.
(different from putMVar on full MVar.)
|
|
| newEmptySampleVar :: IO (SampleVar a) |
| Build a new, empty, SampleVar |
|
| newSampleVar :: a -> IO (SampleVar a) |
| Build a SampleVar with an initial value. |
|
| emptySampleVar :: SampleVar a -> IO () |
| If the SampleVar is full, leave it empty. Otherwise, do nothing. |
|
| readSampleVar :: SampleVar a -> IO a |
| Wait for a value to become available, then take it and return. |
|
| writeSampleVar :: SampleVar a -> a -> IO () |
| Write a value into the SampleVar, overwriting any previous value that
was there. |
|
| Produced by Haddock version 0.4 |
