Re: Proposed patch - psql wraps at window width

From: Gregory Stark <stark(at)enterprisedb(dot)com>
To: "Bruce Momjian" <bruce(at)momjian(dot)us>
Cc: "Brendan Jurd" <direvus(at)gmail(dot)com>, "PostgreSQL-development" <pgsql-hackers(at)postgresql(dot)org>, "Bryce Nesbitt" <bryce2(at)obviously(dot)com>, <heikki(at)enterprisedb(dot)com>
Subject: Re: Proposed patch - psql wraps at window width
Date: 2008-04-24 12:05:35
Message-ID: 87bq3z8nlc.fsf@oxford.xeocode.com
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"Bruce Momjian" <bruce(at)momjian(dot)us> writes:

> Gregory Stark wrote:
>
>> Earlier I suggested -- and nobody refuted -- that we should follow the
>> precedents of ls and man and other tools which need to find the terminal
>> width: Explicitly set width takes precedence always, if it's not explicitly
>> set then you use the ioctl, and if that fails then you use the COLUMNS
>> environment variable.
>
> Yes, I like that better. Patch updated, same URL:
>
> ftp://momjian.us/pub/postgresql/mypatches/wrap

I think it should just be:

if (opt->format == PRINT_WRAP)
{
/* Get terminal width -- explicit setting takes precedence */
output_columns = opt->columns;

#ifdef TIOCGWINSZ
if (output_columns == 0 && isatty(fout))
{
struct winsize screen_size;

if (ioctl(fileno(fout), TIOCGWINSZ, &screen_size) != -1)
output_columns = screen_size.ws_col;
}
#endif

if (output_columns == 0)
{
const char *columns_env = getenv("COLUMNS");

if (columns_env)
output_columns = atoi(columns_env);
}

if (output_columns == 0)
output_columns = 79;
}

The differences this makes are that:

a) if you do -o /dev/tty (perhaps on some kind of cronjob) it will use the
ioctl.

b) If you dump to a file it will still respect COLUMNS. This might be a bit
weird since bash sets COLUMNS so your file width will be based on the size
of your terminal. But people also do things like COLUMNS=120 psql -o f ...

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
Ask me about EnterpriseDB's 24x7 Postgres support!

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