locking

问题 I'm writing a library project for multiple APPs to use. And for some reason, I must make a function mutual exclusion for different APPs, so I need a cross-process lock. But as far as I know, in android APPs can only write to it's own file's directory in internal storage, and external storage is unreliable because some device don't have one. So file lock seems not applicable for me, so is there any other way to implement cross-process lock? thanks~ 回答1: If you do not want to (or you can not)

问题 I'm writing a library project for multiple APPs to use. And for some reason, I must make a function mutual exclusion for different APPs, so I need a cross-process lock. But as far as I know, in android APPs can only write to it's own file's directory in internal storage, and external storage is unreliable because some device don't have one. So file lock seems not applicable for me, so is there any other way to implement cross-process lock? thanks~ 回答1: If you do not want to (or you can not)

问题 This question already has answers here : What is the difference between a synchronized method and synchronized block in Java? [duplicate] (6 answers) Closed 2 years ago . what is the difference between public synchronized void addition() { //something; } and public void addtion() { synchronized (//something) { //something; } } If I am wrong Ignore this question. 回答1: it the first one only one thread can execute whole method at a time whereas in second one only one thread can execute that

问题 This question already has answers here : What is the difference between a synchronized method and synchronized block in Java? [duplicate] (6 answers) Closed 2 years ago . what is the difference between public synchronized void addition() { //something; } and public void addtion() { synchronized (//something) { //something; } } If I am wrong Ignore this question. 回答1: it the first one only one thread can execute whole method at a time whereas in second one only one thread can execute that

问题 This question already has answers here : What is the difference between a synchronized method and synchronized block in Java? [duplicate] (6 answers) Closed 2 years ago . what is the difference between public synchronized void addition() { //something; } and public void addtion() { synchronized (//something) { //something; } } If I am wrong Ignore this question. 回答1: it the first one only one thread can execute whole method at a time whereas in second one only one thread can execute that

问题 I'm trying to reduce the memory usage for the lock objects of segmented data. See my questions here and here. Or just assume you have a byte array and every 16 bytes can (de)serialize into an object. Let us call this a "row" with row length of 16 bytes. Now if you modify such a row from a writer thread and read from multiple threads you need locking. And if you have a byte array size of 1MB (1024*1024) this means 65536 rows and the same number of locks. This is a bit too much, also that I

问题 This is kind of follow up to one of my earlier question here. In summary I am trying to come up with a lock free design for this scenario where I upon cancellation of task I want to call a method of third party library. In response to my question, a helpful SO participant suggested to use CancellationToken.Register but I am not sure where and how can I use that here. Below is code that I come up with. Please let me know if you see any issue with this approach or if there are any better

问题 I have a C application that uses pthreads. There is a lock contention between two threads(say A and B) where A gets the lock first while B is waiting for the lock, Once A is done and releases the lock, B still doesn't get it and after a while A gets the lock again(A does acquire and release in a loop). If I attach my process to gdb and pause thread A after it has given up the lock and manually continue on thread B, it then gets it and does what is needed. This does not look like a dead lock

问题 My MVC application is handling searches via a standard search box on a webpage. I'm trying to keep track of a user's searches - if they type a new search then I want to cancel their previous search and launch the new one. I'm using a dictionary of sessionIDs and Searcher objects (my object that has a method Search() in it. The issue I'm having is the flag to say SearchInProgress is never appearing as false and so the function that cancels a search is never called. Possibly due to using a lock

问题 I would like to use the max_time_ms flag during a find on mongodb, but I woulld like to understand how this flag works and how to verify that it is working. pymongo find().max_time_ms(500) Is there any way to verify? I tried to db.fsyncLock() , but I get this is applicable only for inserts. I thought that a possible solution should be insert too many entries and reduce to max_time_ms(1) , so the query will not have enough time to take results. Any suggestions? Tks 回答1: Passing the max_time_ms