[Libpqxx-general] adopting stateless cursor

[Madden, Don (DCOR)]

Hi,

 

I am a new user of libpqxx and I am using version 3.0.3 of  libpqxx. I
am creating a  "stateless cursor" below and then use then in later
transactions, i will be adopting this stateless cursor.  See an example
snippet of code below involving T1, cur1 and T2, cur2. I cannot create
"cur2" as the complier will not create the underlying SQL cursor as
there is no "sql_cursor" that takes 4 arguments of transaction, adopted
cursor name, update policy and ownership policy. Instead the SQL cursor
expects 3 arguments - transaction, cursor name and ownership policy.
Please see the details below via an example , the flagged compiler error
and the constructor definitions for this problem.

 

As i am new to libpqxx, is there something stupid that I'm doing?

 

Thanks,

Don

 

Example showing problem with adopting stateless cursor

============================================

 

    work T1(cnx, "stateless cursor");      

    string query = "select relname from pg_class;";

    const string cursorRefName = "loose cursor";

    stateless_cursor<cursor_base::read_only, cursor_base::loose>
cur1(T1, query, cursorRefName, true);

 

    work T2(cnx, "stateless adaptor cursor");      

    stateless_cursor<cursor_base::read_only, cursor_base::loose>
cur2(T2, cursorRefName);

 

    cur1.close();

 

Compiler errors with adopting stateless cursor

====================================

 

/usr/include/pqxx/cursor.hxx: In constructor 'pqxx::stateless_cursor<up,
op>::stateless_cursor(pqxx::transaction_base&, std::string) [with
pqxx::cursor_base::updatepolicy up = read_only,
pqxx::cursor_base::ownershippolicy op = loose]':

testFdrsTransactors.cc:931:   instantiated from here

/usr/include/pqxx/cursor.hxx:310: error: no matching function for call
to 'pqxx::internal::sql_cursor::sql_cursor(pqxx::transaction_base&,
const std::string&, pqxx::cursor_base::updatepolicy,
pqxx::cursor_base::ownershippolicy)'

/usr/include/pqxx/cursor.hxx:207: note: candidates are:
pqxx::internal::sql_cursor::sql_cursor(pqxx::transaction_base&, const
std::string&, pqxx::cursor_base::ownershippolicy)

/usr/include/pqxx/cursor.hxx:203: note:
pqxx::internal::sql_cursor::sql_cursor(pqxx::transaction_base&, const
std::string&, const std::string&, pqxx::cursor_base::accesspolicy,
pqxx::cursor_base::updatepolicy, pqxx::cursor_base::ownershippolicy,
bool)

/usr/include/pqxx/cursor.hxx:195: note:
pqxx::internal::sql_cursor::sql_cursor(const
pqxx::internal::sql_cursor&)

make: *** [testFdrsTransactors.o] EtD

 

 

Header code defining stateless_cursor and sql_cursor

=========================================

/// Adopt existing scrolling SQL cursor.

  stateless_cursor(

                transaction_base &trans,

                const PGSTD::string adopted_cursor) :

    m_cur(trans, adopted_cursor, up, op)

  {

    // Put cursor in known position

    m_cur.move(cursor_base::backward_all());

  }

 

 

sql_cursor(transaction_base &t,

                const PGSTD::string &cname,

                cursor_base::ownershippolicy op);



 
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