method

freeze

v1_9_3_392 - Show latest stable - Class: Object

freeze()

public

Prevents further modifications to obj. A RuntimeError will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?.

This method returns self.

a = [ "a", "b", "c" ]
a.freeze
a << "z"

produces:

prog.rb:3:in `<<': can't modify frozen array (RuntimeError)
 from prog.rb:3

VALUE
rb_obj_freeze(VALUE obj)
{
    if (!OBJ_FROZEN(obj)) {
        if (rb_safe_level() >= 4 && !OBJ_UNTRUSTED(obj)) {
            rb_raise(rb_eSecurityError, "Insecure: can't freeze object");
        }
        OBJ_FREEZE(obj);
        if (SPECIAL_CONST_P(obj)) {
            if (!immediate_frozen_tbl) {
                immediate_frozen_tbl = st_init_numtable();
            }
            st_insert(immediate_frozen_tbl, obj, (st_data_t)Qtrue);
        }
    }
    return obj;
}

freeze

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