isatty gives different results depending on wheter cargo run is used

[saghm]

Depending on whether a binary is run directly or with cargo run, isatty() seems to give different results. For example, given the following code:

fn main() {
    let fileno = unsafe { libc::STDIN_FILENO as i32 };
    let isatty = unsafe { libc::isatty(fileno) };
    println!("fileno: {}, isatty: {}", fileno, isatty);
}

When run with cargo run, the output is

fileno: 0, isatty: 0

However, when the binary is directly run, the output is

fileno: 0, isatty: 0

I'm not sure if this is expected or not, or if it's fixable from Rust rather than from the C implementation, but I thought I was worth checking just in case.

EDIT: I'm realizing this is more like caused by something in Cargo than libc, so there's probably nothing that can be done from here.

[posborne]

The output appears to be the same in the sample you provided? Did you paste the wrong output for one of the two?

[saghm]

Sorry, forgot to mention this only happens on the latest nightly (2016-03-24), not any earlier nightlies or on stable.

[alexcrichton]

I believe this is a dupe of rust-lang/rust#32254 caused by rust-lang/rust#31618 and fixed in rust-lang/rust#32257, so closing in favor of rust-lang/rust#32254 but thanks for the report!