ziglings/exercises/088_async5.zig
2021-06-30 19:59:25 -04:00

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//
// Sure, we can solve our async value problem with a global
// variable. But this hardly seems like an ideal solution.
//
// So how do we REALLY get return values from async functions?
//
// The 'await' keyword waits for an async function to complete
// and then captures its return value.
//
// fn foo() u32 {
// return 5;
// }
//
// var foo_frame = async foo(); // invoke and get frame
// var value = await foo_frame; // await result using frame
//
// The above example is just a silly way to call foo() and get 5
// back. But if foo() did something more interesting such as wait
// for a network response to get that 5, our code would pause
// until the value was ready.
//
// As you can see, async/await basically splits a function call
// into two parts:
//
// 1. Invoke the function ('async')
// 2. Getting the return value ('await')
//
// Also notice that a 'suspend' keyword does NOT need to exist in
// a function to be called in an async context.
//
// Please use 'await' to get the string returned by
// getPageTitle().
//
const print = @import("std").debug.print;
pub fn main() void {
var myframe = async getPageTitle("http://example.com");
var value = ???
print("{s}\n", .{value});
}
fn getPageTitle(url: []const u8) []const u8 {
// Please PRETEND this is actually making a network request.
_ = url;
return "Example Title.";
}