member?

/*
 *  call-seq:
 *     enum.include?(obj)     => true or false
 *     enum.member?(obj)      => true or false
 *
 *  Returns <code>true</code> if any member of <i>enum</i> equals
 *  <i>obj</i>. Equality is tested using <code>==</code>.
 *
 *     IO.constants.include? "SEEK_SET"          #=> true
 *     IO.constants.include? "SEEK_NO_FURTHER"   #=> false
 *
 */

static VALUE
enum_member(obj, val)
    VALUE obj, val;
{
    VALUE memo[2];

    memo[0] = val;
    memo[1] = Qfalse;
    rb_iterate(rb_each, obj, member_i, (VALUE)memo);
    return memo[1];
}