Promise Management

Functions for working with fetch promises. More...

Functions
bool	fetch_promise_poll (fetch_promise_t *promise)
	Check if a promise has completed (NON-BLOCKING)
bool	fetch_promise_await (fetch_promise_t *promise, uint32_t timeout_ms)
	Wait for a promise to complete (BLOCKING)
bool	fetch_promise_cancel (fetch_promise_t *promise, const char *reason)
	Cancel a pending promise.
bool	fetch_promise_cancelled (const fetch_promise_t *promise)
	Check if a promise was cancelled.

Detailed Description

Functions for working with fetch promises.

Function Documentation

fetch_promise_await()

bool fetch_promise_await	(	fetch_promise_t *	promise,
		uint32_t	timeout_ms )

Wait for a promise to complete (BLOCKING)

This function blocks the calling thread and drives the event loop internally until the promise completes or times out.

Parameters

promise	The promise to wait for
timeout_ms	Maximum time to wait in milliseconds (0 for infinite)

Returns

true if promise completed within timeout, false if timed out

Warning

This function BLOCKS the calling thread

Note

Event Loop: Drives the event loop internally while waiting

// BLOCKING approach (simpler but blocks thread)
fetch_promise_t *promise = fetch_async("https://httpbin.org/get", NULL);
 
if (fetch_promise_await(promise, 5000)) { // Blocks for up to 5 seconds
    if (fetch_promise_fulfilled(promise)) {
        printf("Request completed successfully\n");
    } else {
        printf("Request failed\n");
    }
} else {
    printf("Request timed out\n");
}
 
fetch_promise_free(promise);

fetch_promise_cancel()

bool fetch_promise_cancel	(	fetch_promise_t *	promise,
		const char *	reason )

Cancel a pending promise.

Parameters

promise	The promise to cancel
reason	Optional reason for cancellation

Returns

true if promise was cancelled, false if already completed

fetch_promise_t *promise = fetch_async("https://httpbin.org/delay/10", NULL);
 
// Cancel after 2 seconds in a separate thread or timer
if (fetch_promise_cancel(promise, "User cancelled")) {
    printf("Request was cancelled\n");
}
 
fetch_promise_free(promise);

fetch_promise_cancelled()

bool fetch_promise_cancelled

(

const fetch_promise_t *

promise

)

Check if a promise was cancelled.

Parameters

promise

The promise to check

Returns

true if promise was cancelled

fetch_promise_poll()

bool fetch_promise_poll

(

fetch_promise_t *

promise

)

Check if a promise has completed (NON-BLOCKING)

Parameters

promise

The promise to check

Returns

true if promise is completed (fulfilled or rejected), false if still pending

Note

This function does NOT block and does NOT drive the event loop

You must call fetch_event_loop_process() separately to make progress

// CORRECT: Non-blocking polling
fetch_promise_t *promise = fetch_async("https://httpbin.org/get", NULL);
 
while (!fetch_promise_poll(promise)) {
    // Drive the event loop to make progress
    fetch_event_loop_process(10); // Small timeout for responsiveness
 
    // Do other work while waiting
    handle_other_tasks();
}
 
// Promise is now complete