thread '<unnamed>' panicked at 'cannot access stdout during shutdown'

[pakipaki2000]

Hi,

Thanks for the lib :)
Looks like I can't open an environnement inside a thread or even outside, how do you pass the env variable to a thread?

CODE =
let env = unsafe {

  		let mut env_builder = lmdb::EnvBuilder::new().unwrap();
            env_builder.set_mapsize(54975188).unwrap_or_else(|e| {
                panic!("Unable to allocate LMDB space: {:?}", e);
            });

        env_builder.open(
        "/dev/shm/dbs0", lmdb::open::Flags::empty(), 0o600).unwrap()
};


let go = thread::spawn(move || {
example(&format!("/dev/shm/dbs{:?}", 0), env); // Don't mind this function, I've just put a println inside

});

It keep saying:
thread '' panicked at 'cannot access stdout during shutdown', src/libcore/option.rs:1038:5

I tried putting both env variable INSIDE the thread and also OUTSIDE the thread, I don't think I understand why it's working just fine but if I move my whole thing inside a thread it's not working anymore.

PS: Tried also with a mutable &mut env... doesn't work.

Thanks for the help :)

[AltSysrq]

I think something else is going on. I adapted your example, and this code works regardless of whether or not main calls .join().unwrap() on the thread handle: https://gist.github.com/AltSysrq/2dbd2aa891554955409dba08fe979a34 (The body of do_stuff was copied from the crate docs; the sleep_ms() call is to ensure the main thread exits before the thread actually does anything)

Have you tried running with RUST_BACKTRACE=1 to get more information about where exactly the panic is happening?

Unfortunately I'm not really sure what to suggest. The error message appears to correspond to this bug: rust-lang/rust#29488. Some of the comments mention it being platform-dependent; but I was running my test on Linux, and your paths also look Linux-specific to me.

lmdb-zero doesn't use any TLS nor does it have any println!s (much less one in a Drop implementation), so I think there's a chance your issue isn't actually related to LMDB but instead is elsewhere and spawning the extra thread perturbs the timing of things just right for you to run into the problem.

[pakipaki2000]

Thank you!
The problem was because my program was exiting before the thread finished!

Very helpful, have a nice day