Re: [Caml-list] Problem with network example of Ocaml book

[Gerd Stolpmann]

The socket is not bound, so getsockname cannot return anything.
After Unix.bind or Unix.connect the socket will have a "name",
i.e. be bound to a port.

Gerd

Harald Schmidt said:
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> Hash: SHA1
>
> Hi all,
>
> I worked through the network example (page 629) of the the Ocaml book,
and
> don't know what's going wrong with the last statement. I am using Ocaml
> under cygwin / WinXP.
>
> I know, EINVAL means invalid argument, but as far as I read s_descr is
> used
> as an abstract file descriptor. Is this wrong?
>
>
> -
> -----------------------------------------------------------------------
-----
> - -------------------------------------------------
> let my_name = Unix.gethostname ();;
> let my_entry_byname = Unix.gethostbyname my_name;;
> let my_addr = my_entry_byname.Unix.h_addr_list.(0);;
> let my_entry_byaddr = Unix.gethostbyaddr my_addr;;
> let my_full_name = my_entry_byaddr.Unix.h_name;;
> let s_descr = Unix.socket Unix.PF_INET Unix.SOCK_STREAM 0;;
> let (addr_in, p_num) =
> match Unix.getsockname s_descr with
> Unix.ADDR_INET (a,n) -> (a,n)
> | _ -> failwith "not INET";;
>
> # val my_entry_byname : Unix.host_entry =
> {Unix.h_name = "CNCHZUR2497"; Unix.h_aliases = [||];
> Unix.h_addrtype = Unix.PF_INET; Unix.h_addr_list = [|<abstr>;
> <abstr>|]}
> # val my_addr : Unix.inet_addr = <abstr>
> # val my_entry_byaddr : Unix.host_entry =
> {Unix.h_name = "CNCHZUR2497"; Unix.h_aliases = [||];
> Unix.h_addrtype = Unix.PF_INET; Unix.h_addr_list = [|<abstr>|]}
> # val my_full_name : string = "CNCHZUR2497"
> # val s_descr : Unix.file_descr = <abstr>
> # Exception: Unix.Unix_error (Unix.EINVAL, "getsockname", "").
> #
>
> -
> -----------------------------------------------------------------------
-----
> - -------------------------------------------------
>
> By the way: where can I find the domain_of function of page 630. Here i
s
> the
> code I used from the book:
>
>
> Harald
>
>
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------------------------------------------------------------
Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany
ge...@gerd-stolpmann.de http://www.gerd-stolpmann.de
------------------------------------------------------------

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[William D. Neumann]

On Wed, 16 Nov 2005, Harald Schmidt wrote:

> I worked through the network example (page 629) of the the Ocaml book, and
> don't know what's going wrong with the last statement. I am using Ocaml
> under cygwin / WinXP.
>
> I know, EINVAL means invalid argument, but as far as I read s_descr is used
> as an abstract file descriptor. Is this wrong?

Well, this works fine on my OS X and Linux machines, so I'm guessing that
it has something to do with cygwin. Unfortunately I don't know enough
about it to provide much help...

> By the way: where can I find the domain_of function of page 630. Here is the

> code I used from the book:

Do you mean the one in the "A Generic Server" section (page 632 in my
copy)? If so, I have no idea where theirs comes from, but you can use
the Unix.domain_of_socket function in the Unix library.

William D. Neumann

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