026_hello2.zig

//
// Great news! Now we know enough to understand a "real" Hello World
// program in Zig - one that uses the system Standard Out resource...which
// can fail!
//
const std = @import("std");

// Take note that this main() definition now returns "!void" rather
// than just "void".
// Since there's no specific error type, this means
// that Zig will infer the error type. This is appropriate in the case
// of main(), but can have consequences elsewhere.
pub fn main() !void { // todo x: !void 类型,

    // We get a Writer for Standard Out so we can print() to it.
    const stdout = std.io.getStdOut().writer();

    // Unlike std.debug.print(), the Standard Out writer can fail
    // with an error. We don't care _what_ the error is, we want
    // to be able to pass it up as a return value of main().
    //
    // We just learned of a single statement which can accomplish this.
    try stdout.print("Hello world!\n", .{}); // todo x: try 来避免 Panic

    // todo x: 捕捉报错
    stdout.print("Hello world!\n", .{}) catch |err| {
        std.debug.print("Error: {}", .{err});
    };
}