mirror of
https://codeberg.org/andyscott/ziglings.git
synced 2024-11-08 11:20:46 -05:00
48 lines
1.4 KiB
Zig
48 lines
1.4 KiB
Zig
|
//
|
||
|
// 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.
|
||
|
return "Example Title.";
|
||
|
}
|