os.time() modifies the argument
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- Subject: os.time() modifies the argument
- From: Nicola Fontana <ntd@...>
- Date: 2017年1月28日 01:04:31 +0100
Hi all,
in a project I'm working on I was testing some time related
functions with a loop similar to the following:
-- This loop does not work in Lua 5.3.3
local datetime = { year=2016, month=6, day=20, isdst=false }
for n = 1, #tests do
local test = tests[n]
datetime.hour = test.hour
datetime.min = test.min
local timestamp = os.time(datetime)
...
end
After some research, I was surprised to discover that os.time()
modifies the datetime table passed in. Here is the proof:
$ lua
Lua 5.3.3 Copyright (C) 1994-2016 Lua.org, PUC-Rio
> a = { year=2016, month=6, day=20, isdst=false }
> for k,v in pairs(a) do print(k,v) end
isdst false
month 6
day 20
year 2016
> os.time(a)
1466420400
> for k,v in pairs(a) do print(k,v) end
sec 0
year 2016
isdst true
wday 2
yday 172
month 6
day 20
min 0
hour 13
Just to be sure I checked against Lua 5.2.4. That worked as expected:
$ lua52
Lua 5.2.4 Copyright (C) 1994-2015 Lua.org, PUC-Rio
> a = { year=2016, month=6, day=20, isdst=false }
> for k,v in pairs(a) do print(k,v) end
day 20
year 2016
isdst false
month 6
> os.time(a)
> for k,v in pairs(a) do print(k,v) end
day 20
year 2016
isdst false
month 6
Is this expected behavior? I did not find anything mentioning it
in PiL or in the wiki.
Ciao.
--
Nicola