Python fromtimestamp OSError

Question

For some reason when constructing datetimes using fromtimestamp, I get a \"OSError [Errno22] Invalid Argument\" when I use negative times less than -43200 (-12hrs). I am on

Answer 1

If the timestamp is out of the range of values supported by the platform C localtime() or gmtime() functions, datetime.fromtimestamp() may raise an exception like you're seeing.

On Windows platform, this range can sometimes be restricted to years in 1970 through 2038. I have never seen this problem on a Linux system.

Answer 2

If you get this error and you're not using an obviously wrong timestamp, check your units.

fromtimestamp expects a timestamp in seconds, whereas it's quite common to get timetstamps in milliseconds (e.g. I found this when trying to parse a timestamp produced from Moment.js in a calendar widget).

Take the timestamp 1523443804214 - it's 11th April 2018, about 15 minutes before I made this post. According to Epoch Converter, no problem, but note: "Assuming that this timestamp is in milliseconds:".

In Python this returns an OSError:

In [15]: datetime.fromtimestamp(1523443804214.0)
---------------------------------------------------------------------------
OSError Traceback (most recent call last)
<ipython-input-15-0c8efd251031> in <module>()
----> 1 datetime.fromtimestamp(1523443804214.0)

However if we divide by a thousand:

In [17]: datetime.fromtimestamp(1523443804.214)
Out[17]: datetime.datetime(2018, 4, 11, 11, 50, 4, 214000)

the result is what we expect.

Answer 3

A timestamp is the number of seconds since January 1st 1970, and this is always a positive value.

Answer 4

@wim's answer is correct, but anyone else arriving here might be interested in testing it (adjust range if you wish):

import datetime
import platform
print(
    "Running on Python ver.{} on {} {}\n" \
    .format(
        platform.python_version(),
        platform.system(),
        platform.release()
        )
)
for timestamp in range(1, 100000000):
    try:
        dt = datetime.datetime.fromtimestamp(timestamp)
    except:
        pass
    else:
        break
print(
    "Smallest accepted Unix timestamp by {}: '{}' ({})" \
    .format(platform.system(), timestamp, dt)
)

What I got was:

A:\src\X.utilities>test.py
Running on Python ver.3.6.1 on Windows 7

Smallest accepted Unix timestamp by Windows: '86400' (1970-01-02 02:00:00)

Answer 5

To solve this problem, divide the timestamp value by 1000.

In Windows, the timestamp number is multiplied by a factor of a 1000.