help:how to get the Nth argument stmt from CALL_EXPR stmt tree

[alert7]

hi,all
        
        
      I don't know how to get the Nth argument stmt  from CALL_EXPR stmt tree?

          the GetCallArgOperands implement this function that i code ,but it 
isn't working :(

          thanks any advice or piece of example code .

//////////////////////////////////////////////////////

 tree GetCallArgOperands(tree stmt ,int i){
 tree func, param, args;
 int j = 1;


  func = get_callee_fndecl (stmt);

  for (param = DECL_ARGUMENTS (func), args = TREE_OPERAND (stmt, 1);
           param && args;
           param = TREE_CHAIN (param), args = TREE_CHAIN (args))
 {
          tree arg = TREE_VALUE (args);
          if (param != arg)
            {
                // FIXME:
            }
          if (j==i)
          {
                  fprintf(stderr,"args ----------\n");
                  debug_tree(arg);
        
                  return default_def (arg); //FIXME: to stmt tree ?
          }
        
          j++;
 }
          return NULL_TREE;
}
/////////////////////////////////////////////////



                                

　　　　　　　　bugs
[EMAIL PROTECTED]
　　　　　　　　　　2005-07-05