[erlang-questions] On OTP rand module difference between OTP 19 and OTP 20

Attila Rajmund Nohl <>
Thu Aug 31 17:32:44 CEST 2017


2017-08-31 17:27 GMT+02:00 Loïc Hoguin <>:
> On 08/31/2017 05:13 PM, Attila Rajmund Nohl wrote:
>>
>> 2017-08-31 15:42 GMT+02:00 Loïc Hoguin <>:
[...]
>>> I certainly hope this is not the general policy for OTP. We program
>>> against
>>> the documentation. The documentation *is* our reality.
>>
>>
>> I disagree. Take this example:
>> https://lwn.net/SubscriberLink/732420/9b9f8f2825f1877f/ The printk()
>> function in the Linux kernel was documented to print new logs to new
>> lines unless the KERN_CONT option was passed. In reality it didn't
>> always started new lines and people expected (maybe even relied on)
>> this - and when the code was updated to match the documentation, they
>> were genuinely surprised when their code was broken.
>
>
> This story is not about people following the documentation and then have the
> documentation be "fixed" under their feet without them noticing, it is in
> fact the complete opposite.

The moral of the story: people are programming against
behavior/implementation, not documentation. In these cases fixing the
implementation instead of the documentation has very real possibility
of breaking existing programs. Of course, one can tell its users that
"it's your fault you haven't followed the documentation!" but it
doesn't necessarily make those users happy...


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