R_Interactive {was '[Rd] stdout == 'Terminal' or 'File'}

Simon Urbanek Simon.Urbanek at math.uni-augsburg.de
Wed May 12 11:47:49 CEST 2004

while the topic is on, something remotely related although the same:

On May 12, 2004, at 10:04 AM, Prof Brian Ripley wrote:

> interactive() is as good a test as we have, and I think if a better 
> test
> is required in the interactive case, the user should be asked.

There may be a little problem in the current sources (talking unix for 
now) - R sets the interactive flag like this:

system.c at 248:    R_Interactive = isatty(0);

Unfortunately right after this there comes:

if (!R_Interactive && SaveAction != SA_SAVE && SaveAction != SA_NOSAVE)
    R_Suicide("you must specify `--save', `--no-save' or `--vanilla'");

Now speaking of embedded R - the above leaves (afaik) no way of telling 
R to use interactive mode before this suicide attempt if stdout is no 
tty (it doesn't have to if the embedding app provides its own 
Read/WriteConsole etc.). Any thoughts on this? (btw: aqua uses a hack 
to circumvent this... whenever aqua needs a hack it may be worth 
thinking about something more general ;))


Simon Urbanek
Department of computer oriented statistics and data analysis
University of Augsburg
Universitätsstr. 14
86135 Augsburg

Tel: +49-821-598-2236
Fax: +49-821-598-2200

Simon.Urbanek at Math.Uni-Augsburg.de

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