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Cc: Caml Mailing List <caml-list@inria.fr>
From: Dustin Sallings <dustin@spy.net>
Subject: Re: [Caml-list] GC and file descriptors
Date: Wed, 12 Nov 2003 20:09:06 -0800
To: David Fox <david.fox@lindows.com>
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> Dustin Sallings wrote:
>
>>
>>     I keep ending up with somewhat awkward structures to close files 
>> I've opened.  Does the GC take care of any of this type of thing?


On Nov 12, 2003, at 17:18, David Fox wrote:

> I might start with this
>
> let for_process_output f cmd =
>   let r = Unix.open_process_in cmd in
>   let result = f r in
>   Unix.close_process_in r;
>   result
>
> then
>
> let tput x = for_process_output (fun r -> input r buf 0 8) ("tput " ^ 
> x)
>
> at which point you start thinking about exception handling...

	Well, I didn't see the close_process thing, but that made things a bit 
worse.  My goal is to capture the output of a command with each of two 
args.  I currently have this:

exception SubprocessError of string;;

(* Get a string from the tput command. *)
let tput x =
     let r = Unix.open_process_in ("tput " ^ x)
     and buf = String.create 8 in
     let len = input r buf 0 8 in
     let status = Unix.close_process_in r in
     begin
     match status with
         Unix.WEXITED(st) -> if (st != 0) then
                         raise (SubprocessError "Non-zero exit status");
         | _ -> raise (SubprocessError "Unknown error.");
     end;
     String.sub buf 0 len
;;

(* The two characters we need. *)
let smso = tput "smso";;
let rmso = tput "rmso";;

	This is to give me the equivalent of the following bourne shell:

smso=`tput smso`
rmso=`tput rmso`

	Garbage collecting the subprocesses and file descriptors would make 
this a bit more straightforward.

--
SPY                      My girlfriend asked me which one I like better.
pub  1024/3CAE01D5 1994/11/03 Dustin Sallings <dustin@spy.net>
|    Key fingerprint =  87 02 57 08 02 D0 DA D6  C8 0F 3E 65 51 98 D8 BE
L_______________________ I hope the answer won't upset her. ____________

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