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From: Erwin Rol <>
Subject: Re: [ptxdist] year 2038 Toolchain
Date: Thu, 23 May 2024 13:52:44 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 5/23/24 12:38, Ian Abbott wrote:
> On 23/05/2024 07:41, Erwin Rol wrote:

>> The following code;
>> auto t = std::chrono::system_clock::now();
>> does not seem to work correctly. When the system date is less than 
>> 2038 it works and gives back the correct time, but for dates > 2038 it 
>> seems to return some 1970 date.
> I guess that libstdc++ in the toolchain would need to be rebuilt with 
> 64-bit time_t support.  Although <chrono> uses a 64-bit integer type 
> internally, some of the functions such as 
> std::chrono::system_clock::now() use compiled in code that picks up the 
> C system time ABI at the time libstdc++ was built.  So now() will read 
> the system time using the 32-bit system time ABI (so will suffer from 
> Y2038 problems) and convert it to its own internal 64-bit integer type. 
> Other functions such as 
> std::chrono::system_clock::from_time_t(std::time_t) are not compiled in 
> so will use whatever C system time ABI was selected when <chrono> was 
> included.

I believe libstd++ uses gettimeofday internally, which should use time_t 
for the seconds field, which should be 64bit if _TIME_BITS=64 is 
defined. I just hacked the Toolchain to try it, but it is a slow 
process, build toolchain -> build project -> test :-)

If I figure it out I'll let you guys know (so it can be added to the 
official Toolchain)

- Erwin

  reply	other threads:[~2024-05-23 11:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-23  6:41 Erwin Rol
2024-05-23 10:38 ` Ian Abbott
2024-05-23 11:52   ` Erwin Rol [this message]
2024-05-24  8:41     ` Ian Abbott
2024-05-24  9:04       ` Erwin Rol
2024-05-24 10:19         ` Michael Olbrich
2024-05-27  8:32           ` Erwin Rol
2024-05-27 10:34             ` Christian Melki
2024-05-23  6:57 Erwin Rol

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