help -- cursor inside a function

hello ,
i have a procedure as below.

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create function retrec(integer) returns integer
as
'declare
uid alias for $1;
begin
declare retrec_cur cursor for select * from jd_user_master where
um_user_id>uid;
if found then
fetch 1 from retrec_cur;
move next from retrec_cur;
return 1;
end if;
end;'
language 'plpgsql';
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this gets created , but while running it i get the error below,
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NOTICE: plpgsql: ERROR during compile of retrec near line 5
ERROR: parse error at or near "cursor"
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why this is so ? can anyone help me out ? thanx in advance.