promise_create

NAME

promise_create - create a new pending promise

SYNOPSIS

promise promise_create();

DESCRIPTION

Returns a new promise in the pending state, with no declared payload
type -- it is a `promise<mixed>`, assignable to any `promise<T>`
variable. (Only an `async` function's own promise carries a declared
payload; see the async/await concept page.)

A promise is a first-class
LPC value (`typeof` returns `"promise"`) holding the eventual result of
an asynchronous operation. It settles exactly once, either fulfilled via
promise_resolve(3) or rejected via promise_reject(3); reactions attached
with promise_then(3) run from the microtask drain after settlement --
never synchronously, but still within the same gametick.

Promises compare by identity (`p == q` is true only for the same
promise) and may be used as mapping keys. They are not saved by
save_object(3).

EXAMPLES

```c
promise delay(int seconds) {
    promise p = promise_create();
    call_out( (: promise_resolve, p, 1 :), seconds);
    return p;
}
```

SEE ALSO

promise_resolve(3), promise_reject(3), promise_then(3),
promise_status(3), promise_result(3)