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View Source Overview The OTP Design Principles define how to structure Erlang code in terms of processes, modules, and directories. Supervision Trees A basic concept in Erlang/OTP is the supervision tree. This is a process structuring model based on the idea of workers and supervisors: Workers are processes that perform computations and other actual work.Supervisors are processes that monitor work

View Source The Erlang mode for Emacs Purpose The purpose of this user guide is to introduce you to the Erlang mode for Emacs and gives some relevant background information of the functions and features. See also Erlang mode reference manual The purpose of the Erlang mode itself is to facilitate the developing process for the Erlang programmer. Pre-requisites Basic knowledge of Emacs and Erlang/OT

View Source Introduction This section is a quick start tutorial to get you started with Erlang. Everything in this section is true, but only part of the truth. For example, only the simplest form of the syntax is shown, not all esoteric forms. Also, parts that are greatly simplified are indicated with manual. This means that a lot more information on the subject is to be found in the Erlang book o

View Source Erlang Distribution over TLS This section describes how the Erlang distribution can use TLS to get extra verification and security. The Erlang distribution can in theory use almost any connection-based protocol as bearer. However, a module that implements the protocol-specific parts of the connection setup is needed. The default distribution module is inet_tcp_dist in the Kernel applic

View Source code (kernel v10.2) Interface to the Erlang code server process. This module contains the interface to the Erlang code server, which deals with the loading of compiled code into a running Erlang runtime system. The runtime system can be started in interactive or embedded mode. Which one is decided by the command-line flag -mode: % erl -mode embedded The modes are as follows: In interac

View Source Expressions In this section, all valid Erlang expressions are listed. When writing Erlang programs, it is also allowed to use macro and record expressions. However, these expressions are expanded during compilation and are in that sense not true Erlang expressions. Macro and record expressions are covered in separate sections: PreprocessorRecords Expression Evaluation All subexpression

View Source erl Start the Erlang runtime system. Description The erl program starts an Erlang runtime system. The exact details (for example, whether erl is a script or a program and which other programs it calls) are system-dependent. NoteIf you are using Erlang/OTP 25 or earlier on Windows and want to start an Erlang system with full shell support, you should use werl.exe. See the Erlang/OTP 25

View Source Mnesia System Information The following topics are included: Database configuration dataCore dumpsDumping tablesCheckpointsStartup files, log file, and data filesLoading tables at startupRecovery from communication failureRecovery of transactionsBackup, restore, fallback, and disaster recovery Database Configuration Data The following two functions can be used to retrieve system inform

View Source Constructing and Matching Binaries This section gives a few examples on how to handle binaries in an efficient way. The sections that follow take an in-depth look at how binaries are implemented and how to best take advantages of the optimizations done by the compiler and runtime system. Binaries can be efficiently built in the following way: DO my_list_to_binary(List) -> my_list_to_bi

View Source Types and Function Specifications The Erlang Type Language Erlang is a dynamically typed language. Still, it comes with a notation for declaring sets of Erlang terms to form a particular type. This effectively forms specific subtypes of the set of all Erlang terms. Subsequently, these types can be used to specify types of record fields and also the argument and return types of function

Possibly the most important feature of an editor designed for programmers is the ability to indent a line of code in accordance with the structure of the programming language. The Erlang mode does, of course, provide this feature. The layout used is based on the common use of the language. The mode also provides things as syntax highlighting, electric commands, module name verification, comment su

View Source How to Implement a Driver NoteThis section was written a long time ago. Most of it is still valid, as it explains important concepts, but this was written for an older driver interface so the examples do not work anymore. The reader is encouraged to read the erl_driver and driver_entry documentation also. Introduction This section describes how to build your own driver for Erlang. A dr

Mnesia Database Questions Cover Expand All Contract AllTable of Contents What is Erlang Top of chapter In a nutshell, what is Erlang? What is OTP? What sort of applications is Erlang particularly suitable for? What sort of problems is Erlang not particularly suitable for? Who uses Erlang for product development? Who uses Erlang for research and teaching? Can I get commercial support for Erlang? Qu

View Source slave (stdlib v6.2) This module provides functions for starting Erlang slave nodes. All slave nodes that are started by a master terminate automatically when the master terminates. All terminal output produced at the slave is sent back to the master node. File I/O is done through the master. Slave nodes on other hosts than the current one are started with the ssh program. The user must

View Source re (stdlib v6.2) This module contains regular expression matching functions for strings and binaries. The regular expression syntax and semantics resemble that of Perl. The matching algorithms of the library are based on the PCRE library, but not all of the PCRE library is interfaced and some parts of the library go beyond what PCRE offers. Currently PCRE version 8.40 (release date 201

View Source erlang (erts v15.2) The Erlang BIFs and predefined types. By convention, most Built-In Functions (BIFs) and all predefined types are included in this module. Some of the BIFs and all of the predefined types are viewed more or less as part of the Erlang programming language and are auto-imported. Thus, it is not necessary to specify the module name. For example, the calls atom_to_list(e

Concurrent Programming Definitions Creating a new process Simple message passing An Echo Process Selective Message Reception Selection of Any Message A Telephony Example Pids can be sent in messages Registered Processes The Client Server Model Timeouts Definitions Process - A concurrent activity. A complete virtual machine. The system may have many concurrent processes executing at the same time.

Download Erlang/OTP The latest version of Erlang/OTP is 27.1. To install Erlang you can either build it from source or use a pre-built package. Take a look at the Erlang/OTP 27 release description to see what changes Erlang/OTP 27 brings over the previous major version. The Erlang/OTP version scheme is described in the Erlang/OTP Systems Principles Guide. Compiling Erlang from source # You can bui

View Source gen_tcp (kernel v10.0.1) Interface to TCP/IP sockets. This module provides functions for communicating over TCP/IP protocol sockets. The following code fragment is a simple example of a client connecting to a server at port 5678, transferring a binary, and closing the connection: client() -> SomeHostInNet = "localhost", % to make it runnable on one machine {ok, Sock} = gen_tcp:connect(

View Source mnesia (mnesia v4.23.3) A distributed key-value DBMS The following are some of the most important and attractive capabilities provided by Mnesia: A relational/object hybrid data model that is suitable for telecommunications applications.A DBMS query language, Query List Comprehension (QLC) as an add-on library.Persistence. Tables can be coherently kept on disc and in the main memory.Re