Error: 'assertion failed: libc::CloseHandle(native) != 0' if integer is too high.

[mdinger]

Code:

use std::io::println;

fn main() {

    for num in range(0, 100000) {
        spawn(proc() {
            for i in range(0,100000) {
                let x = i*i;
                }
        });
    }
}

Compile and run:

$ rustc hello.rs
...
$ hello.exe
task '<main>' failed at 'assertion failed: libc::CloseHandle(native) != 0', C:\b
ot\slave\dist2-win\build\src\libstd\rt\thread.rs:181

$

This works with 1,000 but not 100,000. I'm using Rust 0.10 on Win 7. I didn't try nightlies.

[lifthrasiir]

It seems that we are currently not checking for the error of CreateThread API call in the std::rt::thread::imp::create function. Spawning too many threads causes the invalid handle that is caught by CloseHandle much later. Pretty bad.

@mdinger By the way, the default runtime (libnative) is not designed for spawning lots of tasks. Consider using libgreen for that; the runtime guide will give more information about what is a runtime and how you can switch it.

[mdinger]

Thanks for the tip. I'll look into it.