Function PQsendDescribe

src/interfaces/libpq/fe-exec.c:2488–2539

* PQsendDescribe * Common code to send a Describe command * * Available options for desc_type are * 'S' to describe a prepared statement; or * 'P' to describe a portal. * Returns 1 on success and 0 on failure. */

 * Returns 1 on success and 0 on failure.
 */
static int
PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target)
{
	PGcmdQueueEntry *entry = NULL;

	/* Treat null desc_target as empty string */
	if (!desc_target)
		desc_target = "";

	if (!PQsendQueryStart(conn, true))
		return 0;

	entry = pqAllocCmdQueueEntry(conn);
	if (entry == NULL)
		return 0;				/* error msg already set */

	/* construct the Describe message */
	if (pqPutMsgStart('D', conn) < 0 ||
		pqPutc(desc_type, conn) < 0 ||
		pqPuts(desc_target, conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* construct the Sync message */
	if (conn->pipelineStatus == PQ_PIPELINE_OFF)
	{
		if (pqPutMsgStart('S', conn) < 0 ||
			pqPutMsgEnd(conn) < 0)
			goto sendFailed;
	}

	/* remember we are doing a Describe */
	entry->queryclass = PGQUERY_DESCRIBE;

	/*
	 * Give the data a push (in pipeline mode, only if we're past the size
	 * threshold).  In nonblock mode, don't complain if we're unable to send
	 * it all; PQgetResult() will do any additional flushing needed.
	 */
	if (pqPipelineFlush(conn) < 0)
		goto sendFailed;

	/* OK, it's launched! */
	pqAppendCmdQueueEntry(conn, entry);

	return 1;

sendFailed:
	pqRecycleCmdQueueEntry(conn, entry);
	/* error message should be set up already */
	return 0;
}

/*
 * PQnotifies