reentrancy

问题 I am experimenting on implementing a simple row level locking for google sheets. (Conscious about concurrent accesses butching the data. Am I just being paranoid?). I've come across the LockService and was planning on using it but was just curious what kind of lock it is. 回答1: Answer: LockService is a mutual-exclusion lock, which, if used to guard script-external data, such as the PropertiesService methods which do not use user-specific properties, allow the code to be re-entrant. The Lock

问题 I am experimenting on implementing a simple row level locking for google sheets. (Conscious about concurrent accesses butching the data. Am I just being paranoid?). I've come across the LockService and was planning on using it but was just curious what kind of lock it is. 回答1: Answer: LockService is a mutual-exclusion lock, which, if used to guard script-external data, such as the PropertiesService methods which do not use user-specific properties, allow the code to be re-entrant. The Lock

问题 Reading on locks in C#. I see that being able to acquire lock on same object multiple times is said to be possible because Monitors are re-entrant. The definition of re-entrant code as defined in wikipedia does not seem to fit well in this context. Can you please help me understand what is re-entrancy in the context of C# and how does it apply to Monitors? From what I have understood, when a thread has acquired a lock, it would not relinquish the lock when in the middle of a critical section

问题 My question refers to whether or not the use of a ReentrantLock guarantees visibility of a field in the same respect that the synchronized keyword provides. For example, in the following class A , the field sharedData does not need to be declared volatile as the synchronized keyword is used. class A { private double sharedData; public synchronized void method() { double temp = sharedData; temp *= 2.5; sharedData = temp + 1; } } For next example using a ReentrantLock however, is the volatile

问题 This code was taken from the 3rd edition of Advanced Programming in the UNIX Environment, written by Richard Stevens. This is an example of how to make a reentrant version of getenv() . It is demostrated here only for a learning purpose. /* Copyright (c) W.R.Stevens */ #include <string.h> #include <errno.h> #include <pthread.h> #include <stdlib.h> extern char **environ; pthread_mutex_t env_mutex; static pthread_once_t init_done = PTHREAD_ONCE_INIT; static void thread_init(void) { pthread

问题 I've found a reentrancy problem when using NotifyIcons. It's really easy to reproduce, just drop a NotiftIcon on a form and the click event should look like this: private bool reentrancyDetected; private void notifyIcon1_MouseClick(object sender, MouseEventArgs e) { if (reentrancyDetected) MessageBox.Show("Reentrancy"); reentrancyDetected = true; lock (thisLock) { //do nothing } reentrancyDetected = false; } Also start a background thread which will cause some contention: private readonly

问题 I'm learning how to use reentrant Bison and Flex together. I already got a simple calculator working without the reentrant capability. However when I activated the reentrant feature and made the necessary modifications, I couldn't get this to work. Here is the code: scanner.l %{ #include <stdio.h> #include "parser.tab.h" %} %option 8bit reentrant bison-bridge %option warn noyywrap nodefault %option header-file="lex.yy.h" DIGIT [0-9] %% "+" { return ADD; } "-" { return SUB; } "*" { return MUL;

问题 I was going through a re-entrancy guide on recommended practices when writing re-entrant code. What other references and resources cover this topic? What lint-like tools can be used to check for these issues? 回答1: The guide is sufficient. My personal rule of thumbs are only 2 for re-reentering code: take only pass by value parameters, used only value passed in as parameters in the function. if I need to use any global parameters or pointer (for performance or storage sake), use a mutex or

问题 I'm new to Java and OOP. I'm reading concurrency in java and in chapter 2, it talks about re-entrancy. I don't quite understand how a deadlock situation would occur. Can some one break this situation down for me to understand the details line by line? Thank you in advance. If intrinsic locks were not reentrant, the call to super.doSomething would never be able to acquire the lock because it would be considered already held, and the thread would permanently stall waiting for a lock it can

问题 I'd like to write a SIGSEGV handler that writes messages to a file (FILE *). I've heard that fprintf is not reentrant and should not be called inside a signal handler. Is there a reentrant version of it, or any other function that provides formatted file I/O that can be called inside a signal handler? 回答1: No. According to §7.14.1.1 ¶5 of version N1570 of the C11 standard: If [the] signal occurs […], the behavior is undefined if […] the signal handler calls any function in the standard