erlang | 易学教程

centos7 安装RabbitMQ3.6.15

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centos7 安装RabbitMQ3.6.15 以及各种报错(转) 各个版本之间的差异不大，安装前要确保rabbitmq 的版本和 elang的版本一致。预防各种错乱。注意点：（重要！！重要！！）同时安装的时候最好确保rabbitmq和erlang放在通过目录下面。我安装的路径是在：/usr/local/ rabbitMQ3.6.15对应的erlang的版本是20.3 1、安装Erlang环境 [root@izwz9cwq2lgbd7zagmw4ynz local]# yum install gcc glibc-devel make ncurses-devel openssl-devel xmlto // 安装依赖文件 [root@izwz9cwq2lgbd7zagmw4ynz local]# wget -c http://erlang.org/download/otp_src_20.3.tar.gz // 安装erlang [root@izwz9cwq2lgbd7zagmw4ynz local]# tar -zxvf otp_src_20.3.tar.gz // 解压 [root@izwz9cwq2lgbd7zagmw4ynz local]# cd otp_src_20.3/ // 编译安装，编译后放在/usr/local/erlang目录里面 [root

Compiling project with NIFs with rebar: cl.exe not found

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问题 I'm new to erlang and rebar. In my rebar project I used a dependency containing native c code and during rebar compile I'm getting error: Name cl.exe is not recognized as an internal or external command, operable program or batch file I guess that rebar is trying to compile c files from my dependency using Microsoft's cl.exe compiler from VisualStudio, right? The problem is that I don't have VS installed and don't want to install it. Why rebar is trying to use cl.exe? Can I configure rebar to

win7下安装RabbitMQ

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RabbitMQ依赖erlang,所以先安装erlang，然后再安装RabbitMQ; 下载RabbitMQ,下载地址： rabbitmq-server-3.5.6.exe 和erlang，下载地址： otp_win64_18.1.exe 先安装erlang,双击erlang的安装文件即可，然后配置环境变量： ERLANG_HOME=D:\Program Files\erl7.1 追加到path=%ERLANG_HOME%\bin; 验证erlang是否安装成功，打开cmd命令窗口，进入erlang的bin路径，输入erl命令，如果出现如下提示，则说明erlang安装成功： D:\Program Files\erl7.1\bin>erl Eshell V7.1 (abort with ^G) 再安装RabbitMQ，双击安装文件即可，安装完毕后，设置环境变量： RABBITMQ_SERVER=D:\Program Files\RabbitMQ Server\rabbitmq_server-3.5.6 追加到path=%RABBITMQ_SERVER%\sbin; 验证RabbitMQ是否安装成功，在CMD命令窗口输入： C:\Windows\system32>rabbitmq-service ********************* Service control usage

windows下安装rabbitmq

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1、下载下载 rabbitMQ ： http://www.rabbitmq.com/download.html ，安装rabbitmq需要erlang，下载erlang： http://www.erlang.org/download.html 2、安装RABBITMQ rabbitMQ安装，查看安装文档： http://www.rabbitmq.com/install-windows.html 3、安装ERLANG，下载完成ERLANG后，直接打开文件下一步就可以安装完成了，安装完成ERLANG后再回过来安装RABBITMQ。 4、启动RABBITMQ 如果是安装版的直接在开始那里找到安装目录点击启动即可启动的时候有可能碰到这个问题。碰到这种情况的时候就先执行停止，执行完后再启动即可。 5、安装管理工具参考官方文档： http://www.rabbitmq.com/management.html 操作起来很简单，只需要在DOS下面，进入安装目录（F:\RabbitMQ Server\rabbitmq_server-3.5.3\sbin）执行如下命令就可以成功安装。 rabbitmq-plugins enable rabbitmq_management 可以通过访问 http://localhost:15672 进行测试，默认的登陆账号为：guest，密码为：guest。

Which DB (SQL) is better supported in Erlang?

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问题 What do you recommend me to use with Erlang -- MySQL or Postgres ? Which DB has better (more mature, more stable, faster) driver for Erlang ? 回答1: The Erlang ODBC interface can be used to connect to any database that has an ODBC driver. This is officially supported and can be used with both MySQL and Postgres. There is a 100% Erlang driver for Postgres called PGSQL. This is not part of OTP and I am not sure about its quality. 来源： https://stackoverflow.com/questions/2534447/which-db-sql-is

erlang，rabbitMQ，mqtt安装配置

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1、官网下载erlang，rabbitMQ软件。推进地址：（1） http://www.erlang.org/downloads （2） http://www.rabbitmq.com/download.html 2、设置erlang的环境变量： ERLANG_HOME：C:\Program Files\erl9.0 %ERLANG_HOME%\bin; 加入到Path中。 windows键+R键，输入cmd，再输入erl，看到版本号就说明erlang安装成功了 3、安装完rabbitmq-server后，在sbin目录下，执行如下：（1）激活 RabbitMQ's Management Plugin（必须）（2）rabbitmq-plugins enable rabbitmq_mqtt （如果需要使用到MQTT）（3）rabbitmq-plugins list（查看激活的插件） 4 访问网址访问测试 http://localhost:15672 默认账号密码：guest/guest 5、注意 RabbitMQ 默认端口号： 4369 (epmd), 25672 (Erlang distribution) 5672, 5671 (AMQP 0-9-1 without and with TLS) 15672 (if management plugin is enabled

How to concat lists in erlang without creating nested lists?

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问题 I'm trying to be a good erlanger and avoid "++". I need to add a tuple to the end of a list without creating a nested list (and hopefully without having to build it backwards and reverse it). Given tuple T and lists L0 and L1: When I use [T|L0] I get [tuple,list0] . But when I use [L0|T] , I get nested list [[list0]|tuple] . Similarly, [L0|L1] returns [[list0]|list1] . Removing the outside list brackets L0|[T] produces a syntax error. Why is "|" not symmetric? Is there a way to do what I want

erlang interface to python

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问题 I've been expanding on python version of Armstrong's classical example of interfaces. Everything works fine while I communicate bytes. But, I'd like to communicate long integers and floats. Mabye even (oh, no) strings. Here is my code: http://pastebin.com/epxgDmvu http://pastebin.com/rD7CWRkz First of all, all that I know how to send are bytes. Can erlang send anything else to it's inteface? Or do I have to convert float to list of bytes, send it to python and then assemble it back to float

2019.3版本ideal上配置erlang SDK

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1.先安装插件 2.选择erlang的SDK即可来源： https://www.cnblogs.com/lyz-2019-12-05/p/12011910.html

How to identify the exact memory size of an ETS table?

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问题 Give an ETS table with data, the info/1 function returns various properties for the table, including a size value which is specific to the number of rows rather than the physical size. Is there any way to calculate the amount of memory in bytes occupied by an ETS table ? ets:new( mytable, [bag, named_table, compressed]), ets:insert( mytable, { Key, Value } ), .... ets:info ( mytable ). 回答1: TL;DR: ETS table allocated memory size in bytes: ets:info(Table,memory) * erlang:system_info(wordsize).