[erlang-bugs] erlang,hd,[[]]

Vitaliy Kulchevych <>
Mon Feb 11 09:24:07 CET 2013


Hi, Robert!

Yes, it's true.
When os:cmd("LANG=C LC_ALL=C uptime")  calling on loaded system there
returns empty string.
I think os:cmd has timeout.
May be cpu_sup must be catch it?

On Mon, Feb 11, 2013 at 2:35 AM, Robert Virding
<> wrote:
> You are crashing because you are trying to call hd([]) which is illegal as hd/1 returns the head of the argument list and [] has no head. Hence the badarg error. Why it is calling hd([]) in cpu_sup:get_uint32/2 is another story. Can't help you there.
>
> Robert
>
> ----- Original Message -----
>> From: "Vitaliy Kulchevych" <>
>> To: 
>> Sent: Friday, 8 February, 2013 2:17:18 PM
>> Subject: [erlang-bugs] erlang,hd,[[]]
>>
>> Hi, all!
>> I'm using cpu_sup for monitoring os of erlang node. Sometimes I catch
>> crash:
>>
>> {badarg,[{erlang,hd,[[]],[]},{cpu_sup,get_uint32_measurement,2,[{file,"cpu_sup.erl"},{line,282}]},{cpu_sup,measurement_server_loop,1,[{file,"cpu_sup.erl"},{line,585}]}]}
>>
>>
>> Darwin coolchevy.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug
>> 23
>> 16:25:48 PDT 2012; root:xnu-1699.32.7~1/RELEASE_X86_64 x86_64
>>
>> Mac OS X 10.7.5
>>
>> Erlang from mac ports: Erlang R15B (erts-5.9)
>>
>> --
>> live free or die;
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>> erlang-bugs mailing list
>> 
>> http://erlang.org/mailman/listinfo/erlang-bugs
>>



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