I defined the sybase procedure as following:
*******************************************************
create proc circul.circul_hold
	@rec_ctrl_id 		char(10),
	@reader_barcode 	char(14),
	@department_id  	char(2),
	@user_id		char(4),
	@list_no 		int		 output,
	@errmsg		        varchar(200) 	 output
as
......
***********************************************************
and I ececuted this proc in test.php as fllowing:
<?php
include "../include/connect.php";
....
$rec_ctrl_id='15400';
$barcode='21113000694135';
$departid='70';
$userid = 'web';    
$sql = "declare @list_no2 int, @errmsg2 varchar(200) ";
$sql.= "exec circul.circul_hold
'$rec_ctrl_id','$barcode','$departid','$userid',@list_no
=@list_no2 output,@errmsg=@errmsg2 output ";
$sql.= "select list_no = @list_no2 , errmsg = @errmsg2";
$query=sybase_query($sql);
if ($query){
    $array = sybase_fetch_array($query);
    echo $array[list_no] .'<br>';	
    echo $array[errmsg] .'<br>';	
}
...
?>
 I found that $array[list_no]=$array[list_no]=null,and 
 sybase_num_rows($query)=1 and $array[0]= 0,which means
only '0' returns (while the sybase proc excute succeed,it always return 0).
But I execute $sql in SYBASE SQL ADVANTAGE ,I can get 
$array[list_no] and $array[errmsg] ,whilch are not null.

Why?I have been confused for months.
Please tell me the right way to execute sybase proc with output parameters in php as soon as possible.