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