End of Life Ruby 3.1 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

Module#class_variable_defined?

obj.class_variable_defined?(symbol) → true or false

obj.class_variable_defined?(string) → true or false

static VALUE
rb_mod_cvar_defined(VALUE obj, VALUE iv)
{
    ID id = id_for_var(obj, iv, class);

    if (!id) {
        return Qfalse;
    }
    return rb_cvar_defined(obj, id);
}

Returns true if the given class variable is defined in obj. String arguments are converted to symbols.

Example

class Fred
  @@foo = 99
end
Fred.class_variable_defined?(:@@foo)    #=> true
Fred.class_variable_defined?(:@@bar)    #=> false

See also #class_exec #class_variable_get #class_eval #class_variables also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.0

‹ prev#class_exec next ›#class_variable_get