file_writer_example.zig

//! example of opening a file and writing to it with a writer (0.15.1+)

const std = @import("std");

pub fn some_child_fn(
    writer: *std.io.Writer,
) !void
{
    try writer.print("write from child_fn\n", .{});
}

test "open a file and use a writer to write stuff to it"
{
    // write directly
    const fpath = "/var/tmp/test.txt";
    var outfile = try std.fs.cwd().createFile(
        fpath,
        .{},
    );
    defer outfile.close();

    // write via writer object
    var buf:[1024]u8 = @splat(0);
    var writer_root = outfile.writer(&buf);
    const writer = &writer_root.interface;
    try writer.print("Hello, {s}\n", .{ "first line" });

    // pass to child
    try some_child_fn(writer);

    try writer.flush();
}