write

What is the difference between `O_DIRECT | O_SYNC` + write() and `O_DIRECT` + write() + fsync()

由 随声附和 提交于 2021-02-11 12:49:01
问题 I want to know the difference between char *text = (char *)malloc(4096); memset(text, 'a', 4096); int fd = open(filepath, O_RDWR | O_CREAT | O_DIRECT); for(int i=0; i<1000; i++) { write(fd, (void *)text, 4096); fsync(fd); } close (fd); and char *text = (char *)malloc(4096); memset(text, 'a', 4096); int fd = open(filepath, O_RDWR | O_CREAT | O_DIRECT | O_SYNC); //<----Difference for(int i=0; i<1000; i++) { write(fd, (void *)text, 4096); // fsync(fd); <------------------------------------------

Python Write MIDI file

由 故事扮演 提交于 2020-12-12 09:15:52
问题 I want to write a MIDI file with the inputs I receive from the digital piano I have connected. I am using pygame.midi to open an input port and midiutil to write the MIDI file. What I can't wrap my head around is the timing. For example, in addNote(track, channel, pitch, time, duration, volume) , how do I know what time and duration of a note is? When reading a note, I get pitch and volume just fine, but the others I have no idea... I tried using the timestamp but to no avail, it places the

Python Write MIDI file

由 岁酱吖の 提交于 2020-12-12 09:13:18
问题 I want to write a MIDI file with the inputs I receive from the digital piano I have connected. I am using pygame.midi to open an input port and midiutil to write the MIDI file. What I can't wrap my head around is the timing. For example, in addNote(track, channel, pitch, time, duration, volume) , how do I know what time and duration of a note is? When reading a note, I get pitch and volume just fine, but the others I have no idea... I tried using the timestamp but to no avail, it places the

c# and Unity, update records that have changed to a CSV file

由 故事扮演 提交于 2020-07-22 05:59:07
问题 I'm trying to work with a CSV file that is essentially a database of records. On load of the game I Read in a record and instantiate a prefab button, one at a time with the correct text from the CSV file. It's not always the case that the index of the button will be the same as the index of the record where I got the information in the CSV file. So far I setup a Save function that I want certain records that have changed based on a tricks "name" field to reflect in the CSV file. What would be

Lisp - write to file using low memory footprint

由 我怕爱的太早我们不能终老 提交于 2020-07-03 09:37:44
问题 I have large hash tables that I am writing to disk as an occasional backup. I am finding that as I map the hash tables and write to a file, the RAM usage skyrockets compared to the size of the hash. I am running lisp on emacs with slime and sbcl 2.0.3.176. System is Ubuntu 19.10 on a dell server. Data is multiple levels of hash tables. The basic structure of it is: customer-ht - hash table of structs called customer, keyed on lists of integers, like (1 2), (1 3) (defstruct customer (var1 0)

QT分析之网络编程

由 ≡放荡痞女 提交于 2020-01-23 03:49:54
原文地址：http://blog.163.com/net_worm/blog/static/127702419201002842553382/ 首先对Windows下的网络编程总结一下： 如果是服务器，其WinSDK调用分别为： 1 WSAStartup() -> socket() -> htons() / htonl() -> bind() -> listen() -> accept() -> recv() / send() -> closesocket() -> WSACleanup() 如果是客户端程序，其调用序列为： 1 WSAStartup() -> socket() -> htons() / htonl() -> connect() -> recv() / send() -> closesocket() -> WSACleanup() 前面转贴的客户端（WinSocket温习）程序中，收到信息就在console打印出来然后退出了；在一般的应用中，通常是要一直等待收发消息的，直到程序确认退出才关闭socket。如果用一个轮询就会占用很多的CPU资源，所以很多嵌入式设计中会用一个WaitForMultiObject调用，等待退出命令或者超时，然后退出或进行下一轮信息接受。在Windows平台下也有一些比较高明的设计，使用异步socket，然后用异步选择的办法

SVN服务器搭建详解--权限划分

由 时光总嘲笑我的痴心妄想 提交于 2019-12-08 13:30:17
环境准备 SVN使用场景说明 svn说白了就是一种实现文件共享管理的软件，分成服务器端和客户端，所有的文件都存放在服务器端，每个人可以用客户端把文件取到本地查看，也可以在本地修改后上传到服务器端，这样大家就可以随时获得最新版的文件。 TortoiseSVN 就是最常用的一种SVN客户端软件。checkout的功能就是把服务器端的整个库取到本地来，checkout操作一般只需要用一次，完成checkout之后，再想获得最新版文件时，用的是update而不再需要checkout 这里使用CentOS7.3的阿里云服务器，需要关闭防火墙以及selinux。 [root@iZwz93cntl0pzsqbzlrghnZ ~]# cat /etc/redhat-release CentOS Linux release 7.3.1611 (Core) 查看当前YUM 源 [root@iZwz93cntl0pzsqbzlrghnZ ~]# ll /etc/yum.repos.d/ total 12 -rw-r--r-- 1 root root 675 Sep 17 22:45 CentOS-Base.repo -rw-r--r-- 1 root root 230 Sep 17 22:45 epel.repo -rw-r--r-- 1 root root 202 Sep 17 22:49

CentOS7+Apache+SVN安装配置，并通过HTTP方式访问

由 浪子不回头ぞ 提交于 2019-12-08 12:58:46
(一)SVN服务器搭建 1.安装subversion [root@swarm5 ~]# yum install subversion 已加载插件：fastestmirror, langpacks base | 3.6 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 Loading mirror speeds from cached hostfile * base: mirror.bit.edu.cn * extras: mirror.bit.edu.cn * updates: mirror.bit.edu.cn 正在解决依赖关系 --> 正在检查事务 ---> 软件包 subversion.x86_64.0.1.7.14-11.el7_4 将被 安装 --> 正在处理依赖关系 subversion-libs(x86-64) = 1.7.14-11.el7_4，它被软件包 subversion-1.7.14-11.el7_4.x86_64 需要 --> 正在处理依赖关系 libsvn_wc-1.so.0()(64bit)，它被软件包 subversion-1.7.14-11.el7_4.x86_64 需要 --> 正在处理依赖关系 libsvn_subr-1.so.0()(64bit)，它被软件包

6种对象继承方式

由 会有一股神秘感。 提交于 2019-12-07 10:38:31
1、原型链继承 // 通过将自己的原型继承于另外一个构造函数创建出来的对象,将被继承的对象中的所有属性都存在于__proto__属性中. // 缺点: // 1)原型链继承多个实例的引用属性指向相同,改变一个会影响另一个实例的属性. // 如果是引用类型的,继承的是地址,那么子原型中的引用地址和父对象中的引用地址相同 // 2)不能传递参数 // 因为是原型上继承所以不能传递参数 // 3)继承单一 function Father(){ this.FatherName = "father's 构造函数"; } Father.prototype.age = 40; function Son(){ this.SonNname = "Son's 构造函数"; } //Son的原型继承Father创建出来的对象，相当于继承了Father的全部内容，同时全部都存在Son__proto__属性里 Son.prototype = new Father(); Son.prototype.getSubValue = false; Son.prototype.age1 = 20; var example =new Son(); console.log(example.age); 2、借用构造函数继承 使用call()和apply()将父类构造函数引入到子类函数,使用父类的构造函数来增强子类的实例
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