Date: Sat, 4 Mar 2017 15:08:34 -0800 From: Conrad Meyer <cem@freebsd.org> To: Ed Schouten <ed@nuxi.nl> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r314685 - head/bin/ps Message-ID: <CAG6CVpX_Q9JiW35Po7c4=TDSKy94%2BorFRSk_6u093T%2BbY2NL1Q@mail.gmail.com> In-Reply-To: <CABh_MKnux-yfKhFeuApsZSNgyO1sktA_%2BDphhHQXaZezx92Cpw@mail.gmail.com> References: <201703042238.v24McAD8008837@repo.freebsd.org> <CABh_MKnux-yfKhFeuApsZSNgyO1sktA_%2BDphhHQXaZezx92Cpw@mail.gmail.com>
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Hi Ed,
On Sat, Mar 4, 2017 at 2:58 PM, Ed Schouten <ed@nuxi.nl> wrote:
>> @@ -194,6 +194,8 @@ main(int argc, char *argv[])
>>
>> if ((cols = getenv("COLUMNS")) != NULL && *cols != '\0')
>> termwidth = atoi(cols);
>> + else if (!isatty(STDOUT_FILENO))
>> + termwidth = UNLIMITED;
>> else if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, (char *)&ws) == -1 &&
>> ioctl(STDERR_FILENO, TIOCGWINSZ, (char *)&ws) == -1 &&
>> ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&ws) == -1) ||
>>
>
> I think you can actually go ahead and simplify this a bit:
>
> - If something is a TTY, then our implementation of the TTY layer
> guarantees that TIOCGWINSZ always works.
Do you know if it did in 1990 too? It's hard to tell why Marc@ made
this change way back then. I wasn't sure so I left it alone.
> - If we're only interested in testing stdout whether it's a TTY, I
> think it makes little sense to check TIOCGWINSZ on stdin, stderr.
>
> I think there would therefore be very little harm to use something like this:
>
> | if ((cols = getenv("COLUMNS")) != NULL && *cols != '\0')
> | termwidth = atoi(cols);
> | else if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, (char *)&ws) ==
> -1 && ws.ws_row == 0)
Shouldn't this remain || ws.ws_row == 0?
> | termwidth = UNLIMITED;
> | else
> | termwidth = ws.ws_col - 1;
I had a very similar cleanup in mind (|| instead of &&). But I wasn't
sure if there was any reason TIOCGWINSZ might fail on stdout (and why
that change was added originally).
Best,
Conrad
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