Function term_columns

pager.c:203–232

* Return cached value (if set) or $COLUMNS environment variable (if * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive), * and default to 80 if all else fails. */

 * and default to 80 if all else fails.
 */
int term_columns(void)
{
	static int term_columns_at_startup;

	char *col_string;
	int n_cols;

	if (term_columns_at_startup)
		return term_columns_at_startup;

	term_columns_at_startup = 80;
	term_columns_guessed = 1;

	col_string = getenv("COLUMNS");
	if (col_string && (n_cols = atoi(col_string)) > 0) {
		term_columns_at_startup = n_cols;
		term_columns_guessed = 0;
	}
#ifdef TIOCGWINSZ
	else {
		struct winsize ws;
		if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col) {
			term_columns_at_startup = ws.ws_col;
			term_columns_guessed = 0;
		}
	}
#endif

	return term_columns_at_startup;
}

/*
 * Clear the entire line, leave cursor in first column.