Disable wrilten buf in docker

[Steven Schveighoffer]

On Tuesday, 12 March 2024 at 06:36:09 UTC, zoujiaqing wrote:
> Hi, my application use writeln in docker don't display.
>
>
> Python add -u disable it.
> https://stackoverflow.com/questions/29663459/why-doesnt-python-app-print-anything-when-run-in-a-detached-docker-container


Use setvbuf to switch to line buffering. Then you don’t have to 
manually flush everything

https://en.cppreference.com/w/c/io/setvbuf

-Steve