Function fltk::app::handle_main

pub fn handle_main<I: Into<i32> + Copy + PartialEq + PartialOrd>(
    msg: I
) -> Result<bool, FltkError>

Send a signal to the main window. Integral values from 0 to 30 are reserved. Returns Ok(true) if the event was handled. Returns Ok(false) if the event was not handled.

use fltk::{prelude::*, *};
const CHANGE_FRAME: i32 = 100;
let mut wind = window::Window::default();
let mut but = button::Button::default();
let mut frame = frame::Frame::default();
but.set_callback(move |_| {
    let _ = app::handle_main(CHANGE_FRAME).unwrap();
});
frame.handle(move |f, ev| {
    if ev == CHANGE_FRAME.into() {
        f.set_label("Hello world");
        true
    } else {
        false
    }
});

Errors

Returns Err on error or in use of one of the reserved values.