file_size

Io :: #import "Extensions/Io";
#import "File";

Io.io_run(() {
    Io.write_file("/tmp/jacket-io-size.txt", "12345");

    file, _ := Io.open_file("/tmp/jacket-io-size.txt");
    defer Io.close(*file);

    size, error := Io.file_size(*file);
    assert(error == .NONE && size == 5);
});
file_delete("/tmp/jacket-io-size.txt");

Doesn't run in the browser (only on linux, macos).