Programmer Help

1, Overview Case: write a case to test the read-write lock. Requirements: create three threads to write and five threads to read to test the read-write lock. Basic concepts of read-write lock: Read write locks are also called share exclusive locks. When the read-write lock is locked in read mode, it is locked in shared mode; When it is locked i ...

         Today, I learned Linux user management and recorded it here. 1, Significance of users and user groups 1) Meaning of user existence System resources are limited. How to allocate system resources reasonably? 1. Identity account 2. Authorize author 3. Certification auth The above three 'a' ar ...

Why use the make tool and makefile file   it is very simple for us to compile a helloWorld program with gcc command, because it has only one file. However, when multiple files are compiled into an executable file, the linker is required to link the target file. However, when our project is very large and there are many source files design ...

1, Time zone concept UTC(Universal Time Coordinated) World coordinated time; The time obtained through rigorous calculation is accurate to seconds, and the error is within 0.9s, which is a more accurate world time than GMT. GMT(Greenwich Mean Time) gmt; Greenwich, London, UK, is defined as the place where the 0 ° longitude begins. The e ...

Chapter 1 setting up programming environment Installation environment All Python exercises in this article are applicable to the python 3.6 environment. If the execution fails, you can use the python 3.6 environment. A simple python program, hello_world.py #cat hello_world.py print("Hello Python world!") Run hello_world.py #python hello_ ...

0x00 environment construction Download link https://download.vulnhub.com/bulldog/bulldog.ova target Get root permission to read flag Operating environment Target VM virtual machine startup Attack machine kali win10 Target ip problem (1) Set nat mode to the same network segment as kali (2) If it is set to nat, kali can't scan the ...

1. How many "=" are output? int main() { for(unsigned int i=3;i>=0;i--) putchar('='); } Output countless' = '. The type defined in the loop condition is unsigned int, which is an unsigned integer and has no negative form. That is, the for loop always holds. 2. How do the following three methods of exchanging integ ...

1, Installation of muduo Library 1. Install dependent files muduo uses CMake as the build system, and the installation method is as follows: Install cmake: sudo apt get install cmake muduo relies on Boost and is easy to install: Install the boost library sudo apt get install libboost dev libboost test dev muduo has three non essential dep ...

1. Function introduction This is a smart home control system (model) designed based on Huawei cloud Internet of things platform. The hardware adopts STM32+ESP8266 to complete the cloud combination; Through the cloud platform, you can remotely control various electrical switches at home, and remotely collect information such as home gas, natura ...

1, Basic principles of image coding and compression Since a large number of excellent articles have talked about this on the Internet, I won't write here. The content repetition is meaningless! reference resources: http://blog.csdn.net/newchenxf/article/details/51693753 Compression and decompression is the process of mathematical operatio ...