Re: 23.0.50; source of warning in *shell* buffer

[Peter Dyballa <Peter_Dyballa@Freenet.DE>]

Am 19.10.2007 um 14:46 schrieb Andreas Schwab:

> Peter Dyballa writes:
>
>> When I invoke M-x shell the new buffer starts with:
>>
>> 	Warning: no access to tty (Bad file descriptor).
>> 	Thus no job control in this shell.
>>
>> Where is the source for these messages?
>
> They are most likely coming from the shell.

Ahh, strings reveals them in tcsh! Except the 'Bad file descriptor'  
string, which was found in:

	./src/w32.c:2952:  WSAEBADF                , "Bad file descriptor",

I am sure that I am not using Losedows ...

>
>> What are the criterions for this warning?
>
> Probably the shell could not open /dev/tty, ie. it has no controlling
> terminal.  That happens when the process is using pipes instead of  
> ptys.

Indeed. Tty does not return a pty's name, and lsof shows that FILE  
structs are in use:

	COMMAND  PID USER   FD      NAME
	tcsh    9977 pete   16r     0x04bb9380 file struct, ty=0x6, op=0x3823ec
	tcsh    9977 pete   17w     0x04791b40 file struct, ty=0x6, op=0x3823ec
	tcsh    9977 pete   18w     0x04bb9fb0 file struct, ty=0x6, op=0x3823ec
	tcsh    9977 pete   19r     0x0529d4c0 file struct, ty=0x6, op=0x3823ec

>
>> Which elements are necessary for job control?
>
> The shell needs to be able to manipulate the process group of the
> controlling terminal.

Is this really needed in the *shell* buffer? Term offers a more  
complete terminal emulation. In *terminal* buffer I cannot see the  
warnings and tty returns a pty's name.

--
Mit friedvollen Grüßen

   Pete

The day Microsoft makes something that doesn't suck
is the day they start selling vacuum cleaners.
                                     Ernest Jan Plugge