Mode of Operation¶

The mode of operation specifies how Céu-libuv captures events from the environment (e.g., timers and incoming network traffic) and redirects them to the Céu application. It is implemented in C and is part of Céu-libuv.

Céu-libuv maps each libuv request/callback to a corresponding request/input in Céu. As an example, instead of reading from a stream with uv_read_start, Céu-libuv uses ceu_uv_read_start which generates UV_STREAM_READ input events back to the application, as follows:

#define ceu_uv_read_start(stream) uv_read_start(stream,...,ceu_uv_read_start_cb);

void ceu_uv_read_start_cb(uv_stream_t* stream, ...) {
    <...>
    ceu_input(CEU_INPUT_UV_STREAM_READ, <stream>);
}

Under the hood, Céu-libuv uses one event loop, one timer, and one async libuv handles. The timer manages Céu timers. The async manages Céu asyncs and threads. The main event loop makes continuous calls to uv_run passing UV_RUN_ONCE:

int main (void) {
    ceu_start();
    while (<program-is-running>) {
        uv_run(&loop, UV_RUN_ONCE);         // handles all libuv callbacks
        ceu_input(CEU_INPUT__ASYNC, NULL);  // handles timers and asyncs
    }
    ceu_stop();
}