Function pqSaveWriteError

src/interfaces/libpq/fe-exec.c:811–830

* As above, after appending conn->write_err_msg to whatever other error we * have. This is used when we've detected a write failure and have exhausted * our chances of reporting something else instead. */

 * our chances of reporting something else instead.
 */
static void
pqSaveWriteError(PGconn *conn)
{
	/*
	 * If write_err_msg is null because of previous strdup failure, do what we
	 * can.  (It's likely our machinations here will get OOM failures as well,
	 * but might as well try.)
	 */
	if (conn->write_err_msg)
	{
		appendPQExpBufferStr(&conn->errorMessage, conn->write_err_msg);
		/* Avoid possibly appending the same message twice */
		conn->write_err_msg[0] = '\0';
	}
	else
		appendPQExpBufferStr(&conn->errorMessage,
							 libpq_gettext("write to server failed\n"));

	pqSaveErrorResult(conn);
}

/*
 * This subroutine prepares an async result object for return to the caller.