0.15.2-style Hello World fails

[smlavine]

Attempting to run the following example:

const std = @import("std");

pub fn main() !void {
    var stdout_buffer: [1024]u8 = undefined;
    var stdout_writer = std.fs.File.stdout().writer(&stdout_buffer);
    const stdout = &stdout_writer.interface;

    try stdout.print("Hello, World!\n", .{});

    try stdout.flush(); // Don't forget to flush!
}

fails with the following message:

Compiling...

error: WriteFailed


---
exit with exit code 1
---

[SuperAuguste]

A quick

stdout.flush() catch {
    return stdout_writer.err.?;
};

reveals that the writer is failing on error.Unexpected.

Set stdout_writer.mode = .streaming and the example works. I assume this issue is caused by our underlying @bjorn3/browser_wasi_shim WASI shim not implementing fd_pwrite for ConsoleStdout.

I believe the simplest and most correct solution is implementing fd_pwrite as returning ESPIPE to cause Zig's pwritev to return error.Unseekable. Will do this now! :)