gen_server Hello World

简单的gen_server Hello World程序

代码：
[code]
-module(genserver).
-behaviour(gen_server).
-export([start/0, hello/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).

start() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).

hello(Name) ->
Reply = gen_server:call(?MODULE, {hello, Name}),
io:format("~s~n", [Reply]).

handle_call({hello, Name}, _From, State) ->
Reply = lists:append(["Hello, ", Name, "!"]),
{reply, Reply, State}.

init(_Args) ->
{ok, init}.
handle_cast(_Request, State) ->
{noreply, State}.
handle_info(_Info, State) ->
{noreplay, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
[/code]

编译：
[code]
Eshell> c(genserver).
[/code]

运行：
[code]
Eshell> genserver:start().
Eshell> genserver:hello("Hideto").
[/code]

输出结果：
[code]
Hello, Hideto!
[/code]