Re: Command line way to prevent unbuffered?

[Ethan M. <merritt@u.washington.edu>]

On Monday 10 January 2005 10:46 pm, Ethan Merritt wrote:
> >
> > diff -u -r1.72 plot.c
> > --- plot.c    25 Aug 2004 22:33:16 -0000    1.72
> > +++ plot.c    11 Jan 2005 05:26:21 -0000
> > @@ -422,7 +422,9 @@
> >       * Do any non-X platforms suffer from the same problem?
> >       * EAM - Jan 2004.
> >       */
> > -    setvbuf(stdin, (char *) NULL, _IONBF, 0);
> > +    if (isatty(fileno(stdin))) {
> > +        setvbuf(stdin, (char *) NULL, _IONBF, 0);
> > +    }
> >  #endif
> 
> 
> I see why you want this.  But speed is no good if the program
> does not function properly, and previous experience showed that
> unbuffering the input stream was needed for at least some 
> implementations of piped input.

I have changed my mind.  The behavior is not likely to differ
from user to user, only from one platform to another. So it should
be a configuration option for building on that platform, not a
run-time option on the command line.

How about we wrap the code as follows:

#ifndef UNBUFFERED_STDIN
    setvbuf(stdin, (char *) NULL, _IONBF, 0);
#endif

and you can provide a brief set of instructions for how to set
this conditional compilation flag during the cygwin configuration setup.
I have not used cygwin, so I don't know exactly how that is done.

It would be nice if you also checked that this doesn't interfere
with correct execution of "pause" commands, however, since as I
recall that was one of the original problems this was supposed to fix.
For instance, please check that "mousevariables.dem" works properly with 
buffered input under cygwin. 

-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195