Re: [RFC] diagnostics.c: For terminals, restrict messages to terminal width?

[FX <fxcoudert at gmail dot com>]

OK. But if we rename the function, why not simply terminal_width() ?

FX



> Le 6 dÃc. 2014 Ã 23:14, Tobias Burnus <burnus@net-b.de> a Ãcrit :
> 
> This patch fixes a Fortran diagnostic "regression".
> 
> With the current common diagnostic, the width shown with caret diagnostic is determined by:
> 
>    case OPT_fmessage_length_:
>      pp_set_line_maximum_length (dc->printer, value);
>      diagnostic_set_caret_max_width (dc, value);
> 
> plus
> 
> diagnostic_set_caret_max_width (diagnostic_context *context, int value)
> {
>   /* One minus to account for the leading empty space.  */
>   value = value ? value - 1
>     : (isatty (fileno (pp_buffer (context->printer)->stream))
>       ? getenv_columns () - 1: INT_MAX);
> 
>   if (value <= 0)
>     value = INT_MAX;
> 
>   context->caret_max_width = value;
> }
> 
> where getenv_columns looks at the environment variable COLUMNS.
> 
> Note that -fmessage-length= applies to the error message (wraps) _and_ the caret diagnostic (truncates) while the COLUMNS variable _only_ applies to the caret diagnostic. (BTW: The documentation currently does not mention COLUMNS.)
> 
> On most terminals, which I tried, COLUMNS does not seem to be set. In Fortran, error.c's get_terminal_width has a similar check, but additionally it uses ioctl to determine the terminal width.
> 
> I think with caret diagnostics, it is useful not to exceed the terminal width as having several "empty" lines before the "^" does not really improve the readability. Thus, I would propose to additionally use ioctl. Which rises two questions: (a) Should the COLUMNS environment variable or ioctl have a higher priority? [Fortran ranks ioctl higher; in the patch, for backward compatibilty, I rank COLUMNS higher.] (b) Should ioctl be always used or only for Fortran?
> 
> Comments?
> 
> Tobias
> <diag.diff>