Re: [Queue-developers] Cross-platform termios handling...

[Andrew P. <at...@pe...>]

Hi,

> Based on this description, it's unlikely that Expect sends terminal information 
> over the network. (On the other hand, rlogin and telnet do send terminal 
> information over the network, so perhaps we should look at the code base for 
> these two programs. Ultimately, however, they will have to translate information 
> to termios structures as well -- there's no way to completely get around this. 
    
    The telnet RFC plus the EDIT/Linemode extension RFC contains a pretty
    complete description of the way this is done.
    briefly, telnet defines an 'escape' character, plus a whole of modifiers,
    and during the course of a telnet connection conversations like
    
    (telnet)  DO ECHO
    (telnetd) WILL ECHO
    turns remote echo on.
    (telnet)  DONT ECHO
    (telnetd) WONT ECHO
    turns remote echo off.
    
    (These actually occur in binary, but these are the mnemonics used in 
     the RFC.)
    
    Likewise for edit. The client and server negotiate capabilities, 
    and settle on a combination of line editing in the client and 
    on the remote host. They dont actually transfer termios structures
    or similar across the network, as it was intended as a platform 
    independent virtual terminal, with servers running on all sorts 
    of systems ranging from VAX/VMS, MVS, and UNIX, only one of which
    understood termios at that time. 
    
    Another extension allows the transfer of a users unix environment
    including the TERM environment variable across the connection. 
    
        Hope this helps.
	   Andy

-- 
Dr Andy Phillips                                 at...@pe... 
Pergamentum Solutions                              at...@co...
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