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FW: PQntuples and PQgetvalue problem. - Mailing list pgsql-hackers

From zafer yagmuroglu
Subject FW: PQntuples and PQgetvalue problem.
Date
Msg-id BAY159-W4068634497CF9C3DBF75E2A18B0@phx.gbl
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Hello,

In my C++ program, i want to partition sql table, there is sample code below. It is working right. the problem is after func  called 2 or 3 times in func1, PQntuples results 0 although tablename exist.  Also when i disabled PQntuples at if statement, other psql function PQgetvalue(res) return error that is "row number 0 is out of range 0..-1
there are a couple function call same as func1(to check tablename ), at func. when i disabled one of them another at PQntuples funcx return 0.  
i check so may times. it is so weird.

So i think you can help me.

Best regards.

Zafer,


Sample code : 


func1{
      char cmd[100] = "";
      snprintf(cmd,sizeof(cmd),"select tablename from pg_tables where tablename='%s'",  tablename);

      PGresult *res = PQexec(conn, cmd );

      if (PQresultStatus(res) != PGRES_TUPLES_OK)
       {
             logger.error("PQexec: %s", PQerrorMessage(conn));
             PQclear(res);
             wexit(1);
       }

      if (PQntuples(res) == 0)
        //
      } 

      func {
      PGresult *res;
      func1();
      res=PQexec(conn,"Select count(*) from persons");
      if (PQresultStatus(res) != PGRES_TUPLES_OK)
      {
      printf("PQexec: %s", PQerrorMessage(conn));
      PQclear(res);
      exit(1);
      }
      if( atoi(PQgetvalue(res,0,0)) != 0)
        // some code PQexec()
}
    }

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