undefined | Better HN

0 pointsint_19h2y ago0 comments

A failure to write to stdout should not be unexpected given that stdout is routinely redirected to files or to pipes, both of which can be suddenly closed or otherwise fail from the other direction. Yes, you can't recover in this case, but you should at least properly report the error to stderr before exiting, in a way that lets the end user (rather than app dev) properly diagnose the error.

Now if you fail to write to stderr, yeah, that's a good reason for a console app to panic. The onus is on the user to provide something that is "good enough" in that case.

IMO the real problem is that print() etc defaults to stdout historically, but is used mostly for diagnostic information rather than actual output in practice, so it should really go to stderr instead. This would also take care of various issues with buffering etc.

0 comments

couchand2y ago

Woah woah woah let's not get hasty. We can have panicking and nonpanicking versions of the API (at least until somebody builds the nonpanicking version of Rust, that will be great). The panicking version is for quick, off-the-cuff usage, and the nonpanicking one for production use.

There's value in the Hello, World and println-debugging style print, even if it should be eschewed in most general contexts.

int_19hOP2y ago

I didn't say that there isn't value in "hello world" or println-debugging style print. The point is that both should go to stderr rather than stdout (and then panic if they fail). But for stdout, which is the channel for output and not for logging, the default should be to require error handling.

Consider something as trivial as `cat foo >readonly_file` to see why.

j / k navigate · click thread line to collapse