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Diffstat (limited to 'Demo/threads/sync.py')
| -rw-r--r-- | Demo/threads/sync.py | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Demo/threads/sync.py b/Demo/threads/sync.py index 6cdf3e8..3044724 100644 --- a/Demo/threads/sync.py +++ b/Demo/threads/sync.py @@ -258,6 +258,15 @@ # writing. Then if some other thread is waiting to write, it's # allowed to proceed. Else all threads (if any) waiting to read are # allowed to proceed. +# +# .write_to_read() +# Use instead of a .write_in to declare that the thread is done +# writing but wants to continue reading without other writers +# intervening. If there are other threads waiting to write, they +# are allowed to proceed only if the current thread calls +# .read_out; threads waiting to read are only allowed to proceed +# if there are are no threads waiting to write. (This is a +# weakness of the interface!) import thread @@ -464,6 +473,18 @@ class mrsw: self.readOK.broadcast() self.rwOK.release() + def write_to_read(self): + self.rwOK.acquire() + if not self.writing: + raise ValueError, \ + '.write_to_read() invoked without an active writer' + self.writing = 0 + self.nw = self.nw - 1 + self.nr = self.nr + 1 + if not self.nw: + self.readOK.broadcast() + self.rwOK.release() + # The rest of the file is a test case, that runs a number of parallelized # quicksorts in parallel. If it works, you'll get about 600 lines of # tracing output, with a line like |