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instance method

IO::Buffer::Storage#external?

external? → true or false

static VALUE
rb_io_buffer_external_p(VALUE self)
{
    struct rb_io_buffer_view *buffer = get_io_buffer_view(self);

    return RBOOL(buffer->flags & RB_IO_BUFFER_EXTERNAL);
}

The buffer is external if it references the memory which is not allocated or mapped by the buffer itself.

A buffer created using ::for has an external reference to the string’s memory.

External buffer can’t be resized.