Function helpSQL

src/bin/psql/help.c:529–687

* helpSQL -- help with SQL commands * * Note: we assume caller removed any trailing spaces in "topic". */

 * Note: we assume caller removed any trailing spaces in "topic".
 */
void
helpSQL(const char *topic, unsigned short int pager)
{
#define VALUE_OR_NULL(a) ((a) ? (a) : "")

	if (!topic || strlen(topic) == 0)
	{
		/* Print all the available command names */
		int			screen_width;
		int			ncolumns;
		int			nrows;
		FILE	   *output;
		int			i;
		int			j;

		/* Find screen width to determine how many columns will fit */
#ifdef TIOCGWINSZ
		struct winsize screen_size;

		if (ioctl(fileno(stdout), TIOCGWINSZ, &screen_size) == -1)
			screen_width = 80;	/* ioctl failed, assume 80 */
		else
			screen_width = screen_size.ws_col;
#else
		screen_width = 80;		/* default assumption */
#endif

		ncolumns = (screen_width - 3) / (QL_MAX_CMD_LEN + 1);
		ncolumns = Max(ncolumns, 1);
		nrows = (QL_HELP_COUNT + (ncolumns - 1)) / ncolumns;

		output = PageOutput(nrows + 1, pager ? &(pset.popt.topt) : NULL);

		fputs(_("Available help:\n"), output);

		for (i = 0; i < nrows; i++)
		{
			fprintf(output, "  ");
			for (j = 0; j < ncolumns - 1; j++)
				fprintf(output, "%-*s",
						QL_MAX_CMD_LEN + 1,
						VALUE_OR_NULL(QL_HELP[i + j * nrows].cmd));
			if (i + j * nrows < QL_HELP_COUNT)
				fprintf(output, "%s",
						VALUE_OR_NULL(QL_HELP[i + j * nrows].cmd));
			fputc('\n', output);
		}

		ClosePager(output);
	}
	else
	{
		int			i,
					pass;
		FILE	   *output = NULL;
		size_t		len,
					wordlen,
					j;