End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

IO#write

ios.write(string, ...) → integer

static VALUE
io_write_m(int argc, VALUE *argv, VALUE io)
{
    if (argc != 1) {
        return io_writev(argc, argv, io);
    }
    else {
        VALUE str = argv[0];
        return io_write(io, str, 0);
    }
}

Writes the given strings to ios. The stream must be opened for writing. Arguments that are not a string will be converted to a string using to_s. Returns the number of bytes written in total.

Example

count = $stdout.write("This is", " a test\n")
puts "That was #{count} bytes of data"

produces:

This is a test
That was 15 bytes of data

Ruby version changes

3.0
- IO#wait_readable, IO#wait_writable, IO#read, IO#write and other related methods (e.g. IO#puts, IO#gets) may invoke the scheduler hook io_wait(io, events, timeout) in a non-blocking execution context. [Feature #16786]

See also .write #winsize= #write_nonblock #winsize also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1

‹ prev#winsize= next ›#write_nonblock