September 2013
Intermediate to advanced
548 pages
12h 25m
English
Content preview from Programming Erlang, 2nd Edition
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Alarm Management
When we write our application, we need only one alarm—we’ll raise it when the CPU starts melting because we’re computing a humongous prime (remember, we were making a company that sells prime numbers). This time we’ll use the real OTP alarm handler (and not the simple one we saw at the start of this chapter).
The alarm handler is a callback module for the OTP
gen_event behavior. Here’s the code:
| my_alarm_handler.erl | |
| | -module(my_alarm_handler). |
| | -behaviour(gen_event). |
| | |
| | %% gen_event callbacks |
| | -export([init/1, code_change/3, handle_event/2, handle_call/2, |
| | handle_info/2, terminate/2]). |
| | |
| | %% init(Args) must return {ok, State} |
| | init(Args) -> |
| | io:format("*** my_alarm_handler init:~p~n",[Args]), |
| | {ok, 0}. |
| | |
| | handle_event({set_alarm, ... |
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.