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gen_fsm的学习笔记
网上搜索gen_fsm的例子，90%都是code_lock，依葫芦画瓢弄了下，记录一些学习心得
init(UnLockCode) -> process_flag(trap_exit,true), io:format("init: ~p~n", [UnLockCode]), {ok, locked, {[], UnLockCode}}.
init返回值里面，locked为StateName，{[], UnLockCode}为StateData，在回调函数里面有用
发送event有两种方式
gen_fsm:send_event(code_lock, {button, Digit}).gen_fsm:sync_send_event(code_lock, {button, Digit},100000).
一般采用第一个异步处理
异步的回调函数声明，StateName( Event, StateData)
locked({button, Digit}, {SoFar, UnlockCode}) -> io:format("async buttion: ~p, So far: ~p, Code: ~p~n", [Digit, SoFar, UnlockCode]), InputDigits = lists:append(SoFar, Digit), case InputDigits of UnlockCode -> do_unlock(), {next_state, open, {[], UnlockCode}, 10000}; Incomplete when length(Incomplete)<length(UnlockCode) -> {next_state, locked, {Digit, UnlockCode}, 5000}; Wrong -> delay:delay(10000000000), io:format("wrong passwd: ~p~n", [Wrong]), {next_state, locked, {[], UnlockCode}} end;
同步的回调函数声明，StateName( Event, From,StateData)
locked({button, Digit}, _From,{SoFar, UnlockCode}) -> io:format("sync buttion: ~p, So far: ~p, Code: ~p~n", [Digit, SoFar, UnlockCode]), InputDigits = lists:append(SoFar, Digit), case InputDigits of UnlockCode -> do_unlock(), {next_state, open, {[], UnlockCode}, 10000}; Incomplete when length(Incomplete)<length(UnlockCode) -> {next_state, locked, {Digit, UnlockCode}, 5000}; Wrong -> io:format("wrong passwd: ~p~n", [Wrong]), {next_state, locked, {[], UnlockCode}} end;
另，erl终端测试给gen_fsm:start_link出来的Pid发exit消息，handle_info收不到，取消link以后收到，处理大概如下
handle_info({‘EXIT‘,Pid,Reason}, StateName, Data) -> io:format("exit ~n"), {stop, StateName, Data};
目前看起来进程池部分，用gen_server作为worker比用gen_fsm要简单点，那就gen_server吧
gen_fsm的学习笔记
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