The registration process usages in Erlang distributed nodes _erlang

In the previous article, the registration process associated atoms have global scope, where the global refers to the current Erlang virtual machine, in the distributed, is the current distributed node. Therefore, registering the process-associated atoms in one node cannot be used directly in another node, but must be used with the target node.

Copy Code code as follows:

{regname, Node}! {messages}.

Example

Start a Server node first

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Erl-sname Server

And then operate in the Erlang Shell.

First, briefly introduce several common functions

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% View current node
Node ().
% => ' server@gentoo-pc '

% View all connected nodes
Nodes ().
% => []% no other nodes are connected at this time

% to see if the current node is alive
Is_alive ().
% => True

And get to the point.

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% to start the last program in the previous article
Test:start ().
% waiting for the new message.
% => True

% current node can use TESTP Atom
TESTP! Message.
% New Message:message
% waiting for the new message.
% => Message

Then start another Client node

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Erl-sname Client

In the new Erlang Shell

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Nodes ().
% => []% node not connected at this time

% The current node cannot directly use this atom's
TESTP! {}.
% * * * Exception Error:bad argument
% in operator!/2
% called as TESTP! {}

% need to work with target node
{TESTP, ' server@gentoo-pc '}! {}.
% => {}% statement return value

At this point, the server node receives the message and prints out

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% New message: {}
% waiting for the new message.

Two nodes will remain connected after the first connection between the nodes

In the Client node

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Nodes ().
% => [' server@gentoo-pc ']

In the Server node

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Nodes ().
% => [' client@gentoo-pc ']

End

Of course, this is only a method, because the call function is wrapped in the module, so you can use a remote call to invoke the Test:call method on the Server node.

Functions can be invoked remotely using the CALL/4 method in the RPC module

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% perform apply on node node (Module, Function, Args)
The% call returns result when the call fails, and returns {BADRPC, Reason}
-spec Rpc:call (Node, Module, Function, Args}-> Result | {BADRPC, Reason}

In the Client node

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Rpc:call (' server@gentoo-pc ', test, call, [' Message from other node ']).