race-condition

How does using the try statement avoid a race condition?

由 江枫思渺然 提交于 2019-12-17 09:22:01
问题 When determining whether or not a file exists, how does using the try statement avoid a "race condition"? I'm asking because a highly upvoted answer (update: it was deleted) seems to imply that using os.path.exists() creates an opportunity that would not exist otherwise. The example given is: try: with open(filename): pass except IOError: print 'Oh dear.' But I'm not understanding how that avoids a race condition compared to: if not os.path.exists(filename): print 'Oh dear.' How does calling

How does using the try statement avoid a race condition?

由 。_饼干妹妹 提交于 2019-12-17 09:21:16
问题 When determining whether or not a file exists, how does using the try statement avoid a "race condition"? I'm asking because a highly upvoted answer (update: it was deleted) seems to imply that using os.path.exists() creates an opportunity that would not exist otherwise. The example given is: try: with open(filename): pass except IOError: print 'Oh dear.' But I'm not understanding how that avoids a race condition compared to: if not os.path.exists(filename): print 'Oh dear.' How does calling

jquery ajax call not asynchronous

由 霸气de小男生 提交于 2019-12-14 04:27:32
问题 I am fresh to jQuery's implementation of it's AJAX methods. I have a simple setup that accesses two different pages, one which takes 10 seconds to complete (I have a timer set on it) and one which checks on the status of the first page. The two functions are progressCheck() which requests its page every second with the latest status and beginLogin() which takes 10 seconds to load. I set a value in the user object on the server that both pages access through symfony 1.4. The issue is that the

Cython parallelisation race condition for DFS

由 泪湿孤枕 提交于 2019-12-14 01:55:55
问题 I'm attempting to develop an AI to play a 1-player board game optimally. I'm using a depth-first search to a few levels. I've attempted to speed it up by multithreading the initial loop iterating over all moves and recursing into the game trees. My idea is that each thread will split-up the initial possible move boards into chunks and further evaluate these in a separate recursive function. All functions called are nogil However, I'm encountering what I can only guess is a race condition

Transport Listener and ActiveMq restart

由 浪尽此生 提交于 2019-12-13 19:02:33
问题 I develope JMS application and now I want to add feature that will support broker restart. I have dynamic topics and I should recreate them after my connection will be resumed. Also I should have a possibility to know when broker is down and when it come back. So I try to implement this feature using ActiveMQ failover protocol. I implement TransportListener and in the method "transportInterrupted" I call full disconnect like public void disconnect() throws JMSException { System.out.println("!

Is the Scala List's cons-operator “::” thread-safe?

由 血红的双手。 提交于 2019-12-13 18:17:51
问题 Is the cons-operator :: on a given list thread-safe? For example what happens if 2 threads use the cons-operator on the same list? val listOne = 1::2::3::Nil val listTwo = 4::5::Nil val combinedList = listOne ::: listTwo // thread1 val combinedList2 = listOne ::: 7:8:NIL // thread2 on the same time 回答1: To add to the answer that Jim Collins gave: All operations on immutable data structures are generally thread safe. The list cons operator does not modify the original list, since every list is

Concurrent access to different keys in Map C++

由 ♀尐吖头ヾ 提交于 2019-12-13 12:46:06
问题 I have two threads where one thread "A" inserts a key X to the map and the same key X is being modified by that thread "A" frequently. At a particular point the thread "A" completes modifications to that key X and then thread "B" will read the key "X" and delete the key "X" from the map. While the thread "B" reads and deletes the map , the thread "A" will insert and write some other keys in the map( not the same key X ) concurrently. In this case , does the map needs to be synchronized? As

Possible Race Condition?

由 瘦欲@ 提交于 2019-12-13 06:34:03
问题 I have the below code: <HTML> <HEAD> <SCRIPT> function myFunction(atlasTrackingURL) { var atlasURL = atlasTrackingURL; if (!atlasURL) return; //Build a cache busting mechanism var timestamp = new Date(); var queryString = "?random=" + Math.ceil(Math.random() * 999999999999) + timestamp.getUTCHours() + timestamp.getUTCMinutes() + timestamp.getUTCSeconds(); //Build the final URL atlasURL = atlasURL + queryString; if (!document.getElementsByTagName || !document.createElement || !document

Writing to file and mkdir race conditions C

由 天大地大妈咪最大 提交于 2019-12-13 04:07:24
问题 I made a function that tries to create a directory, and then write a simple file: buffer = "Hello world!"; string url = "a/b/c/d/"; string tmp = ""; string done = ""; while((tmp = GetBaseDir(url)).compare("")!=0){ done+=tmp; mkdir(done.c_str(), 0777); } // GetBaseDir returns "a/", and changes url to "b/c/d/" ofstream file; file.open((url+"file.txt").c_str(),ios::trunc); file << buffer; file.close(); As you can see, it only tries, if there is a failure it just keeps going on. I read that 'open

requirejs race condition - how to block until previous file retrieved

由 本秂侑毒 提交于 2019-12-12 18:35:38
问题 common_tempaltes file is not a requirejs file - rather a file that defines a global variable. common_templates needs hogan . they both are requested more or less at the same time, but race condition is in affect. common_templates sometimes wins so the code fails with "hogan not loaded yet". require(['module1', 'hogan', 'common_templates'], function(Module){ Module.do_stuff() // this module also requires hogan and common_templates to be loaded }); other than nested require, is there a built in
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