2017-08-11 16:39 GMT+02:00 Achilleas Mantzios <ach...@matrix.gatewaynet.com> :
> On 11/08/2017 16:09, Fabiana Zioti wrote: > > Hi! > > I am studying how to program extensions for PostgreSQL in C language. > > In the example to return to return Composite-type Arguments, from the > PostgreSQL 9.6 documentation, I could not make the cash from a cstring to > the HeapTupleHeader type. > > That is, instead of the function receive as a parameter a table: > > CREATE FUNCTION c_overpaid (emp, integer) RETURNS boolean > AS DIRECTORY > > SELECT name, c_overpaid (emp, 1500) AS overpaid > From emp > WHERE name = 'Bill' OR name = 'Sam'; > > And in the code in C receive the argument as: > > HeapTupleHeader t = PG_GETARG_HEAPTUPLEHEADER (0); > > > The sql function would be defined as: > > CREATE FUNCTION c_overpaid (cstring, integer) RETURNS boolean > AS 'DIRECTORY / funcs', 'c_overpaid' > LANGUAGE C STRICT; > > But how would I receive this argument, for example: > Char * str = PG_GETARG_CSTRING (0), > > And do the conversion to the HeapTupleHeader type? > > Hi you have to build tuple first. Later you can got a HeapTupleHeader pl_toolbox has some functions for composite types https://github.com/okbob/pltoolbox Regards Pavel Stehule > > Why do you want to convert this to HeapTupleHeader since this is *not* a > tuple but a string value? What do you want to achieve? IMHO you better > start with simpler examples, make them run, and proceed as you understand > more and more. > > > What do you guys suggest? > > Thanks in advance > > > -- > Achilleas Mantzios > IT DEV Lead > IT DEPT > Dynacom Tankers Mgmt > >
