synchronization

mySQL authoritative database - combined with Firebase

由 放肆的年华 提交于 2019-12-04 06:59:39
We have built a LAMP-stack API application via PHP Laravel. This currently uses a local mySQL instance. We have mostly implemented views in AngularJS. In order to use Firebase, we need to sync data between the authoritative store in mySQL with anything relevant that exists on Firebase, as close to real-time as possible. This means that other parts of the app which are not real-time and don't use Firebase can also serve up fresh content that's very recently been entered into the system. I know that Firebase is essentially a noSQL database in the cloud. My question is - how do I write a wrapper

Possible race condition in std::condition_variable?

由 喜你入骨 提交于 2019-12-04 06:58:04
I've looked into the VC++ implementation of std::condition_variable(lock,pred) , basically, it looks like this: template<class _Predicate> void wait(unique_lock<mutex>& _Lck, _Predicate _Pred) { // wait for signal and test predicate while (!_Pred()) wait(_Lck); } Basically , the naked wait calls _Cnd_waitX which calls _Cnd_wait which calls do_wait which calls cond->_get_cv()->wait(cs); (all of these are in the file cond.c). cond->_get_cv() returns Concurrency::details::stl_condition_variable_interface . If we go to the file primitives.h , we see that under windows 7 and above, we have the

how to make a multithread copy files

由 六月ゝ 毕业季﹏ 提交于 2019-12-04 06:46:05
问题 I want to copy many files in one, but using multiThread,supposing that file A is the file in which different threads copy datas, in this case each thread is meant to copy one file in file A, using this procedure: procedure ConcatenateFiles(const InFileNames: array of string; const OutFileName: string); var i: Integer; InStream, OutStream: TFileStream; begin OutStream := TFileStream.Create(OutFileName, fmCreate); try for i := 0 to high(InFileNames) do begin InStream := TFileStream.Create

AndroidStudio Failed to Sync Gradle project, Failed to find target Google Inc

由 我与影子孤独终老i 提交于 2019-12-04 06:42:30
问题 How can I resolve the Gradle Sync problem? I installed the missing SDK versions but the error shown again. Take a look to the screenshots please... Screenshot 1 Screenshot 2 Thank you in advance. 回答1: Your compileSdkVersion must be a number, not a String Example: android { compileSdkVersion 24 buildToolsVersion "24.0.2" defaultConfig { applicationId "com.yourpackage.yourapp" minSdkVersion 11 targetSdkVersion 24 versionCode 4 versionName "1.3" } ... } 回答2: You also need to open up "build

Running threads in round robin fashion in java

由 妖精的绣舞 提交于 2019-12-04 06:28:18
问题 I am new to Multithreading and synchronization in java. I am trying to achieve a task in which i am given 5 files, each file will be read by one particular thread. Every thread should read one line from file then forward execution to next thread and so on. When all 5 threads read the first line, then again start from thread 1 running line no. 2 of file 1 and so on. Thread ReadThread1 = new Thread(new ReadFile(0)); Thread ReadThread2 = new Thread(new ReadFile(1)); Thread ReadThread3 = new

Synchronization between two processes in C#.?

由 僤鯓⒐⒋嵵緔 提交于 2019-12-04 06:19:49
问题 Is there any way so that we can synchronize two independent processes? Like if they are sharing a resource, I would like to sync them. I am using C#. 回答1: you can use the Mutex class see documentation here : http://msdn.microsoft.com/en-us/library/system.threading.mutex.aspx 回答2: You can use WCF with pipe binding, or named synchronization objects, Mutex for example for synchronization between two processes 回答3: Mutexes will give you cross process sync. You could also implement an API in WCF

Synchronizing access to a doubly-linked list

由 匆匆过客 提交于 2019-12-04 06:18:25
I'm trying to implement a (special kind of) doubly-linked list in C, in a pthreads environment but using only C-wrapped synchronization instructions like atomic CAS, etc. rather than pthread primitives. (The elements of the list are fixed-size chunks of memory and almost surely cannot fit pthread_mutex_t etc. inside them.) I don't actually need full arbitrary doubly-linked list methods, only: insertion at the end of the list deletion from the beginning of the list deletion at arbitrary points in the list based on a pointer to the member to be removed, which was obtained from a source other

Result of a async task is blocking

由 早过忘川 提交于 2019-12-04 06:04:00
问题 I have an issue with a task blocking when I try to retrieve it's result. I have the following piece of code I want executed synchronously (which is why I'm looking for the result) I would ignore the reason each call has to be made (legacy software that requires multiple calls through different layers) the call seems to break down after it starts the task for the final call to be made in the PostCreateProfile, I can see this request never makes it any further than this. if (CreateProfile

Semaphore solution to reader-writer: order between updating reader count and waiting or signaling on read/write binary semaphore?

由 橙三吉。 提交于 2019-12-04 05:55:01
问题 From Operating System Concepts In the solution to the first readers–writers problem, the reader processes share the following data structures: semaphore rw mutex = 1; semaphore mutex = 1; int read_count = 0; do { wait(rw_mutex); . . . /* writing is performed */ . . . signal(rw_mutex); } while (true); Figure 5.11 The structure of a writer process. do { wait(mutex); read count++; if (read_count == 1) wait(rw mutex); signal(mutex); . . . /* reading is performed */ . . . wait(mutex); read count--;

Mono alternative for named Mutex

由 断了今生、忘了曾经 提交于 2019-12-04 05:42:56
On Windows/.NET, a named Mutex can be used to synchronise multiple processes. Unfortunately, Mono doesn't quite support this on Linux. Their release notes say that Linux doesn't support this Windows feature and it would be unreliable to emulate it. It seems best to avoid the proposed hack to enable it anyway. So what are suggested alternatives? I need to make my program safe to run concurrently, only a short section of it needs to be synchronised with other instances. The application eventually needs to be deployed on Ubuntu Linux with Mono 2.10, but for testing, it would be highly appreciated
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