sync​::one

Structs

Once
[src]

Struct sync::one::Once

pub struct Once {
    // some fields omitted
}

A type which can be used to run a one-time global initialization. This type is unsafe to use because it is built on top of the Mutex in this module. It does not know whether the currently running task is in a green or native context, and a blocking mutex should not be used under normal circumstances on a green task.

Despite its unsafety, it is often useful to have a one-time initialization routine run for FFI bindings or related external functionality. This type can only be statically constructed with the ONCE_INIT value.

Example

use sync::one::{Once, ONCE_INIT};

static mut START: Once = ONCE_INIT;
unsafe {
    START.doit(|| {
        // run initialization here
    });
}

Methods

impl Once

fn doit(&self, f: ||)

Perform an initialization routine once and only once. The given closure will be executed if this is the first time doit has been called, and otherwise the routine will not be invoked.

This method will block the calling os thread if another initialization routine is currently running.

When this function returns, it is guaranteed that some initialization has run and completed (it may not be the closure specified).