ziglings/exercises/090_async7.zig
2021-06-14 15:39:49 -04:00

43 lines
1.1 KiB
Zig

//
// Remember how a function with 'suspend' is async and calling an
// async function without the 'async' keyword makes the CALLING
// function async?
//
// fn fooThatMightSuspend(maybe: bool) void {
// if (maybe) suspend {}
// }
//
// fn bar() void {
// fooThatMightSuspend(true); // Now bar() is async!
// }
//
// But if you KNOW the function won't suspend, you can make a
// promise to the compiler with the 'nosuspend' keyword:
//
// fn bar() void {
// nosuspend fooThatMightSuspend(false);
// }
//
// If the function does suspend and YOUR PROMISE TO THE COMPILER
// IS BROKEN, the program will panic at runtime, which is
// probably better than you deserve, you oathbreaker! >:-(
//
const print = @import("std").debug.print;
pub fn main() void {
// The main() function can not be async. But we know
// getBeef() will not suspend with this particular
// invocation. Please make this okay:
var my_beef = getBeef(0);
print("beef? {X}!\n", .{my_beef});
}
fn getBeef(input: u32) u32 {
if (input > 0xDEAD) {
suspend {}
}
return 0xBEEF;
}