I have a PL/pgSQL function callbackfunc
. If I run it with bitwise result and unpack the result in my app, I got 65/0/65/65
(which is 1090535745
). If I return directly result of bitwise operation (1094795585
) and unpack it, I got 65/65/65/65
. Why?
See sample below
CREATE OR REPLACE FUNCTION callbackfunc(value double precision[][][], pos integer[][], VARIADIC userargs text[])
RETURNS double precision
AS $$
DECLARE
var_result double precision;
BEGIN
var_result := (65 << 24 | 65 << 16 | 65 << 8 | 65 << 0);
--var_result := 1094795585;
RETURN var_result;
END;
$$ LANGUAGE 'plpgsql' IMMUTABLE;
It's the operator's precedence. Bitwise-Or is higher than Shift. Your expression will be calculated as
var_result := (((((((65 << 24) | 65) << 16) | 65) << 8) | 65) << 0);
which gives 1090535745 (= 0x41004141). On the opposite
var_result := (65 << 24) | (65 << 16) | (65 << 8) | (65 << 0)
gives 1094795585 (= 0x41414141).
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