Simple Line Editor

Chris Johns chrisj at
Tue Mar 2 23:49:48 UTC 2010

Joel Sherrill wrote:
> On 03/02/2010 09:59 AM, Till Straumann wrote:
>> Eric Norum wrote:
>>> This looks like an interesting project.  As the web page says,
>>> functionality somewhat like readline would be very useful.
>>> The one big requirement is that the code be reentrant to allow for
>>> multiple ssh or telnet 'logins' to the RTEMS machine.  This is
>>> currently the major shortcoming in readline (and the similar 'tecla'
>>> project) since they rely on the termcap library which is non-reentrant.
>> You can build 'tecla' without using curses, ncurses or termcap and you 
>> get a
>> very nice, re-entrant line editor (assumes/supports an ANSI terminal 
>> only).
> That looks like a nice alternative. Any idea on how big the
> resulting library is?

It does look like a nice library.

> (1) verify this meets our technical requirements,

I think size is a very important issue. The shell could do with a weight loss 
program now and adding a line editor that is the same size as the shell is not 
going to help those users with memory constraints.

I see the need for a fully featured line editor and it appears tecla offers 
that but I also see the need for a light weight very basic line editor. The 
project as it exists in the Wiki calls for a refactoring of the existing code 
and I think that project should exist as is. If we want to support other line 
editors in the shell then that is a different project and the shell should be 
modified to do this. A confdefs.h setting could set the line editor used.


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