In Linux, a semaphore is a mechanism for synchronization and mutual exclusion between processes. It can be used to control access to shared resources to avoid race conditions caused by simultaneous access by multiple processes. Linux provides two types of semaphores: System V semaphores and POSIX semaphores. System V semaphores are operated through system calls […]
Tag: map
Analysis of anonymous mapping page fault exception in Linux kernel virtual memory management
Before explaining the anonymous mapping page fault exception, we must first understand what is an anonymous page? Corresponding to the anonymous page is the file page. We should understand the file page well, which is the page that maps the file, such as mapping the file to the virtual memory through mmap and then reading […]
FreeRTOS mutual exclusion semaphore (mutex lock)
1. Mutually exclusive semaphore A mutually exclusive semaphore is actually a binary semaphore with priority inheritance, which is mostly used for mutually exclusive access to shared resources between different tasks. 2. Mutual exclusion semaphore reduces the impact of priority flipping When a mutex semaphore is being used by task L, and a task H also […]
JAVA New Practice 4: Use JAVA to write a map tile download program and merge the tiles into large images in different levels
This article is full of work and uses code directly to show you how to write an autonomous and controllable map tile download program in Java, and merge the tiles into a large image hierarchically so that you can deploy your own tile map in geoserver. The environment covered in this article is as follows: […]
Easypoi map method imports data, List＜Map＜String, String＞＞ Date item data is empty (null) solution
Directory Preface Solution Foreword When using easypoi map to parse an excel file, if the data format of a certain column in the file is date type, then this tool cannot read it, because its source code reads a certain column in date format, and the data must be a string type, it will handle […]
SpringMVC–@RequestMapping annotation
@RequestMapping annotation The function of @RequestMapping annotation The location of the @RequestMapping annotation @RequestMapping annotated properties 1. value attribute 2. method attribute 3. params attribute (understand) Replenish @RequestParam @RequestHeader @RequestBody @RequestBody gets request parameters in json format @ResponseBody @RestController annotation Function of @RequestMapping annotation The function of the @RequestMapping annotation is to associate the request […]
(STL hash) unordered_map
1. unordered series containers In C++98, STL provides a series of associative containers with red-black tree structures at the bottom, including set, multiset, map and multimap. The time complexity of query operations for these containers is O ( log N ) O(logN)O(logN), where N is the number of elements in the container. In order to […]
FreeRTOS binary semaphores and counting semaphores
1. Binary semaphore and counting semaphore binary semaphore concept Queue of length 1 There is no need to care about the storage content, just whether it is empty or not. Application scenarios Synchronization of tasks and tasks, tasks and interrupts block When the task obtains the semaphore, if the semaphore is empty, it enters the […]
[C#] Use of Mapster object mapping
Series of articles [C#] Number generator (define order number rules, fixed characters, serial numbers, business order numbers) Link to this article: https://blog.csdn.net/youcheng_ge/article/details/129129787 [C#] Date range generator (start date, end date) Link to this article: https://blog.csdn.net/youcheng_ge/article/details/129040663 [C#] Component development, calling dll component methods Link to this article: https://blog.csdn.net/youcheng_ge/article/details/129492112 [C#] Use of data entity classes Link to […]
Data structure – (Map and Set) super detailed
Table of Contents 1.What is Map? 1.2 Description of Map.Entry,> 1.3 Description of common methods of Map 1.4TreeMap use cases 2.What is Set? 2.1 Common methods of Set 2.2TreeSet use cases 3. Hash table 3.1 Concept 3.2 Implementation code 3.3 Relationship with java class sets 1.What is Map? Map is an interface class, which does […]