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instance method

IO#fileno

fileno → integer

static VALUE
rb_io_fileno(VALUE io)
{
    rb_io_t *fptr = RFILE(io)->fptr;
    int fd;

    rb_io_check_closed(fptr);
    fd = fptr->fd;
    return INT2FIX(fd);
}

Returns the integer file descriptor for the stream:

Example

$stdin.fileno             # => 0
$stdout.fileno            # => 1
$stderr.fileno            # => 2
File.open('t.txt').fileno # => 10
f.close

IO#to_i is an alias for IO#fileno.

See also #fdatasync #flush #fcntl #fsync also in 4.1 · 4.0 · 3.4 · 3.3 · 3.1 · 3.0

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