From: Raymond Hettinger <python@rcn.com>
Date: Fri, 6 Mar 2009 23:55:28 +0000 (+0000)
Subject: Document the suggested alternative to emtpy() and full().
X-Git-Tag: v3.1a1~9
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=611eaf0e66bfd00d2ee9e25d4ae9648c9dc2f600;p=thirdparty%2FPython%2Fcpython.git

Document the suggested alternative to emtpy() and full().
---

diff --git a/Lib/queue.py b/Lib/queue.py
index 773b680d8c6a..450f845d4431 100644
--- a/Lib/queue.py
+++ b/Lib/queue.py
@@ -91,14 +91,31 @@ class Queue:
         return n
 
     def empty(self):
-        """Return True if the queue is empty, False otherwise (not reliable!)."""
+        """Return True if the queue is empty, False otherwise (not reliable!).
+
+        This method is likely to be removed at some point.  Use qsize() == 0
+        as a direct substitute, but be aware that either approach risks a race
+        condition where a queue can grow before the result of empty() or
+        qsize() can be used.
+
+        To create code that needs to wait for all queued tasks to be
+        completed, the preferred technique is to use the join() method.
+
+        """
         self.mutex.acquire()
         n = not self._qsize()
         self.mutex.release()
         return n
 
     def full(self):
-        """Return True if the queue is full, False otherwise (not reliable!)."""
+        """Return True if the queue is full, False otherwise (not reliable!).
+
+        This method is likely to be removed at some point.  Use qsize() == n
+        as a direct substitute, but be aware that either approach risks a race
+        condition where a queue can shrink before the result of full() or
+        qsize() can be used.
+
+        """
         self.mutex.acquire()
         n = 0 < self.maxsize == self._qsize()
         self.mutex.release()