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/*
* linelength.c: find the terminal line length
* Preferences: 1. MANWIDTH, 2. COLUMNS, 3. ioctl, 4. 80
*
* Originally adapted from Andries Brouwer's man implementation, also
* released under the GPL: authors believed to include Martin Schulze and
* Jon Tombs, dated 1995/09/02.
*
* Changes for man-db copyright (C) 2001, 2003, 2007 Colin Watson.
*
* This file is part of man-db.
*
* man-db is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* man-db is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with man-db; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif /* HAVE_CONFIG_H */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "linelength.h"
#ifndef _PATH_TTY
# define _PATH_TTY "/dev/tty"
#endif /* _PATH_TTY */
static int line_length = -1;
int get_line_length (void)
{
const char *columns;
int width;
#ifdef TIOCGWINSZ
int dev_tty, tty_fd = -1;
#endif
if (line_length != -1)
return line_length;
line_length = 80;
columns = getenv ("MANWIDTH");
if (columns != NULL) {
width = atoi (columns);
if (width > 0)
return line_length = width;
}
columns = getenv ("COLUMNS");
if (columns != NULL) {
width = atoi (columns);
if (width > 0)
return line_length = width;
}
#ifdef TIOCGWINSZ
/* Original TIOCGWINSZ approach was from Jon Tombs.
* We don't require both stdin and stdout to be a tty, and line
* length is primarily a property of output. However, if it happens
* that stdin is connected to a terminal but stdout isn't, then that
* may well be because the user is trying something like
* 'MAN_KEEP_STDERR=1 man foo >/dev/null' to see just the error
* messages, so use the window size from stdin as a fallback.
* In some cases we may have neither (e.g. if man is running inside
* lesspipe); /dev/tty should be a reliable way to get to the
* current tty if it exists.
*/
dev_tty = open (_PATH_TTY, O_RDONLY);
if (dev_tty >= 0)
tty_fd = dev_tty;
else if (isatty (STDOUT_FILENO))
tty_fd = STDOUT_FILENO;
else if (isatty (STDIN_FILENO))
tty_fd = STDIN_FILENO;
if (tty_fd >= 0) {
int ret;
struct winsize wsz;
ret = ioctl (tty_fd, TIOCGWINSZ, &wsz);
if (dev_tty >= 0)
close (dev_tty);
if (ret)
perror ("TIOCGWINSZ failed");
else if (wsz.ws_col)
return line_length = wsz.ws_col;
}
#endif
return line_length = 80;
}
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