Dear Philippe Great, I got the trace, thank you very much. Shen -----原始邮件----- 发件人: "Philippe Veber" 发送时间: 2013-01-24 20:20:52 (星期四) 收件人: "沈胜宇" 抄送: caml-list@inria.fr 主题: Re: [Caml-list] :: how to locate the source of exception Dear Shen, you can run your program in bytecode setting the OCAMLRUNPARAM correctly and you'll see the whole backtrace, like in OCAMLRUNPARAM=b ./myprogram hope this helps, Philippe. 2013/1/24 沈胜宇 Dear all: My program written in ocaml terminate with the following output: Fatal error: exception Invalid_argument("index out of bounds") So how should I find out the lcoation in source code that raise this exception? Shen