The gproc application
The gproc application
=====================
Extended process dictionary.
__Authors:__ Ulf Wiger ([`ulf.wiger@erlang-solutions.com`](mailto:ulf.wiger@erlang-solutions.com)), Joseph Wayne Norton ([`norton@geminimobile.com`](mailto:norton@geminimobile.com)).
Extended process dictionary
Gproc is a process dictionary for Erlang, which provides a number of useful features beyond what the built-in dictionary has:
* Use any term as a process alias
* Register a process under several aliases
* Non-unique properties can be registered simultaneously by many processes
* QLC and match specification interface for efficient queries on the
dictionary
* Await registration, let's you wait until a process registers itself
* Atomically give away registered names and properties to another process
* Counters, and aggregated counters, which automatically maintain the
total of all counters with a given name
* Global registry, with all the above functions applied to a network of nodes
An interesting application of gproc is building publish/subscribe patterns.
Example:
subscribe(EventType) ->
%% Gproc notation: {p, l, Name} means {(p)roperty, (l)ocal, Name}
gproc:reg({p, l, {?MODULE, EventType}}).
notify(EventType, Msg) ->
Key = {?MODULE, EventType},
gproc:send({p, l, Key}, {self(), Key, Msg}).
Gproc has a QuickCheck test suite, covering a fairly large part of the local
gproc functionality, although none of the global registry. It requires a
commercial EQC license, but rebar is smart enough to detect whether EQC is
available, and if it isn't, the code in gproc_eqc.erl will be "defined away".
There is also an eunit suite, covering the basic operations for local and
global gproc.
By default, `./rebar doc` generates Github-flavored Markdown files.If you want to change this, remove the `edoc_opts` line from `rebar.config`.
Gproc was first introduced at the ACM SIGPLAN Erlang Workshop in
Freiburg 2007 ([Paper available here](http://github.com/esl/gproc/blob/env_vars/doc/erlang07-wiger.pdf)).
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