to_sym

/*
 *  call-seq:
 *     fix.to_sym -> aSymbol
 *
 *  Returns the symbol whose integer value is <i>fix</i>. See also
 *  <code>Fixnum#id2name</code>.
 *
 *     fred = :fred.to_i
 *     fred.id2name   #=> "fred"
 *     fred.to_sym    #=> :fred
 */

static VALUE
fix_to_sym(fix)
    VALUE fix;
{
    ID id = FIX2UINT(fix);

    if (rb_id2name(id)) {
        return ID2SYM(id);
    }
    return Qnil;
}