[Caml-list] TIME-OUT

[Caml-list] TIME-OUT

[altavillasalvatore]

Hi All,

My problem is this:

let risposta byte =
let pdu_length = String.length byte in
let my_name =Unix.gethostname() in
let my_entry_byname = Unix.gethostbyname my_name in
let my_addr = my_entry_byname.Unix.h_addr_list.(0) in
let sockaddr = Unix.ADDR_INET(my_addr, 161) in
let sock = Unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
let sock1 =  Unix.ADDR_INET(my_addr, 12346) in
Unix.bind sock sock1;
let w = Unix.sendto sock byte 0 pdu_length [] sockaddr in
let max = 512 in
let buf=ref (String.create max) in
let len, addr =Unix.recvfrom sock !buf 0 max [] in
Unix.close sock;
let answer = String.sub !buf 0 len in
answer

I would want to introduce a Timeout for input operations (a floating-point value representing a time in seconds) of 15 second.

Regards.

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Re: [Caml-list] TIME-OUT

[Michal Moskal]

On Wed, Feb 19, 2003 at 10:08:39AM +0100, altavillasalvatore@libero.it wrote:
> Hi All,
> 
> My problem is this:
> 
> let risposta byte =
> let pdu_length = String.length byte in
> let my_name =Unix.gethostname() in
> let my_entry_byname = Unix.gethostbyname my_name in
> let my_addr = my_entry_byname.Unix.h_addr_list.(0) in
> let sockaddr = Unix.ADDR_INET(my_addr, 161) in
> let sock = Unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
> let sock1 =  Unix.ADDR_INET(my_addr, 12346) in
> Unix.bind sock sock1;
> let w = Unix.sendto sock byte 0 pdu_length [] sockaddr in
> let max = 512 in
> let buf=ref (String.create max) in
> let len, addr =Unix.recvfrom sock !buf 0 max [] in
> Unix.close sock;
> let answer = String.sub !buf 0 len in
> answer
> 
> I would want to introduce a Timeout for input operations (a 
> floating-point value representing a time in seconds) of 15 second.

Either use Unix.select (to wait 15 second until input is available)
or Unix.alarm/Unix.setitimer (to arrange SIGALRM to be delivered in 
15 seconds, so it will break recvfrom). First solution is probably
cleaner and more efficient (and I'm not sure if recvfrom won't 
restart after signal being delivered).

-- 
: Michal Moskal ::::: malekith/at/pld-linux.org :  GCS {C,UL}++++$ a? !tv
: PLD Linux ::::::: Wroclaw University, CS Dept :  {E-,w}-- {b++,e}>+++ h

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Re: [Caml-list] TIME-OUT

[Gerd Stolpmann]

On Wed, 2003-02-19 at 10:08, altavillasalvatore@libero.it wrote:
> Hi All,
> 
> My problem is this:
> 
> let risposta byte =
> let pdu_length = String.length byte in
> let my_name =Unix.gethostname() in
> let my_entry_byname = Unix.gethostbyname my_name in
> let my_addr = my_entry_byname.Unix.h_addr_list.(0) in
> let sockaddr = Unix.ADDR_INET(my_addr, 161) in
> let sock = Unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
> let sock1 =  Unix.ADDR_INET(my_addr, 12346) in
> Unix.bind sock sock1;
> let w = Unix.sendto sock byte 0 pdu_length [] sockaddr in
> let max = 512 in
> let buf=ref (String.create max) in
> let len, addr =Unix.recvfrom sock !buf 0 max [] in
> Unix.close sock;
> let answer = String.sub !buf 0 len in
> answer
> 
> I would want to introduce a Timeout for input operations (a floating-point value representing a time in seconds) of 15 second.

Unix.select is your friend.

let rdlist,_,_ = Unix.select [sock] [] [] 15.0 in
if rdlist = [] then raise Timeout;

Otherwise, rdlist has one member: sock, and the socket has received a
datagram.

Gerd
-- 
------------------------------------------------------------
Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany 
gerd@gerd-stolpmann.de          http://www.gerd-stolpmann.de
------------------------------------------------------------

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RE: [Caml-list] TIME-OUT

[Beck01, Wolfgang]

altavillasalvatore@libero.it wrote 

> I would want to introduce a Timeout for input operations (a floating-point value
> representing a time in seconds) of 15 second.

use 'select':

let rd_ready, wr_ready, exc_ready = select [sock] [][] 15.0
in
match rd_ready with
  h :: _ ->
	Unix.recvfrom h !buf 0 max []
| [] -> (* handle timeout *)

'select' on Windows is restricted to sockets, on Unix you can
use any file_descr.

--
Wolfgang Beck
T-Systems Nova GmbH 
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