failed to set format string via arguments for zoned_time

M ZHA 1

the test code as below:

#include <iostream>  
#include <chrono>  
using namespace std::chrono;  
  
int main()  
{  
zoned_time zt(current_zone(), system_clock::now());  
std::cout << std::format("{:%T}", zt) << std::endl;  
std::cout << std::format("{:{}}", zt, "%T") << std::endl;  
}

the output:
22:50:48.6959767
2022-08-14 22:50:48.6959767 GMT+8

David Lowndes 4,711 Reputation points

2022-08-15T15:38:02.437+00:00

Just to clarify, what do you think is wrong with the output you get?
You appear to be trying to have the format type as a nested parameter. I can't find any examples that would indicate that's intended to be possible - though I could well be wrong.
M ZHA 1 Reputation point

2022-08-16T14:24:48.093+00:00

I seem to have misunderstood: the second output should be same as the first. it look like below:

form: https://en.cppreference.com/w/cpp/utility/format/formatter#Standard_format_specification
I want to implment the date&time is shown via a format from configuration. Now it looks like I'm going to have to find another way!
David Lowndes 4,711 Reputation points

2022-08-16T14:40:06.713+00:00

None of those example illustrate that you can pass the format type as a nested parameter though.

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failed to set format string via arguments for zoned_time