Sending ctrl-d through a socket

[Scott]

I am using a TCPIP connection to communicate over port 23 (telnet) to
a server,
and I am having to mimic normal command line interface you owuld see
in a telnet session (i.e. I have to write to this socket just like you
would enter things on the keyboard if you telneted to this server).

In a normal telnet session you can enter some commands which take a
long time to complete, and they run in the background and you get the
command line prompt back, you can hit <ctrl-d> on the keyboard to see
the status of the background task and see if you get a response like
"EXECUTED" or "WORKIGN", when you hit the <enter> again you will be
back at the command line to continue working.

Context is C++ on a Unix server:
My problem is I cannot programatically mimic a <ctrl-d> input through
the socket when required, so that I can read the background response.

I have tried writing/sending all sort's of characters to emulate the
keyboard sequence of ctrl-d. I am surprised that I cannot find
anything in the usergroups related to this problem, perhaps control
characters are most usually read but never sent?

I have tried the following, but it did not work:
const char ch='^D';
ptr=&ch[0];
size=1;
nwritten = write(socketDes criptor, ptr, size);

[Gianni Mariani]

Re: Sending ctrl-d through a socket

Scott wrote:
....[color=blue]
> I have tried writing/sending all sort's of characters to emulate the
> keyboard sequence of ctrl-d. I am surprised that I cannot find
> anything in the usergroups related to this problem, perhaps control
> characters are most usually read but never sent?
>
> I have tried the following, but it did not work:
> const char ch='^D';[/color]

const char ch='\004';
[color=blue]
> ptr=&ch[0];
> size=1;
> nwritten = write(socketDes criptor, ptr, size);[/color]

nwritten = write(socketDes criptor, &ch, size);

Maybe ?

[Karl Heinz Buchegger]

Re: Sending ctrl-d through a socket



Scott wrote:[color=blue]
>
> I am using a TCPIP connection to communicate over port 23 (telnet) to
> a server,
> and I am having to mimic normal command line interface you owuld see
> in a telnet session (i.e. I have to write to this socket just like you
> would enter things on the keyboard if you telneted to this server).
>
> In a normal telnet session you can enter some commands which take a
> long time to complete, and they run in the background and you get the
> command line prompt back, you can hit <ctrl-d> on the keyboard to see
> the status of the background task and see if you get a response like
> "EXECUTED" or "WORKIGN", when you hit the <enter> again you will be
> back at the command line to continue working.
>
> Context is C++ on a Unix server:
> My problem is I cannot programatically mimic a <ctrl-d> input through
> the socket when required, so that I can read the background response.
>
> I have tried writing/sending all sort's of characters to emulate the
> keyboard sequence of ctrl-d. I am surprised that I cannot find
> anything in the usergroups related to this problem, perhaps control
> characters are most usually read but never sent?
>
> I have tried the following, but it did not work:
> const char ch='^D';[/color]

those are 2 characters. '^' followed by the character 'D'
[color=blue]
> ptr=&ch[0];
> size=1;
> nwritten = write(socketDes criptor, ptr, size);[/color]

you need to send the character code for your system
On an ASCII system that would be

const char ch = 0x04;

ctrl a -> 0x01
ctrl b -> 0x02
ctrl c -> 0x03
....

--
Karl Heinz Buchegger
kbuchegg@gascad .at

[White Wolf]

Re: Sending ctrl-d through a socket

klaas wrote:
[SNIP][color=blue]
> use EOF, it's a sumbolis integer constant defined in <iostream>,[/color]
[SNIP]

sumbolis as symbolic?

--
WW aka Attila

[Kevin Goodsell]

Re: Sending ctrl-d through a socket

klaas wrote:
[color=blue]
>[color=green]
>> My problem is I cannot programatically mimic a <ctrl-d> input through
>> the socket when required, so that I can read the background response.
>>
>> I have tried writing/sending all sort's of characters to emulate the
>> keyboard sequence of ctrl-d.[/color]
>
> control-d on unix means end-of-file
> on windows this would be control-z
>
> if you want it, you can use
> #include <iostream>
>
> using std::flush;
>
> socket_or_howev er_your_interfa ce_is << EOF << flush;[/color]

This has basically no chance of working. EOF is an integer. This will
print a string representation of it's value. Try it.

-Kevin
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