without disconnect()

(gdb) bt
#0  0x00007ffff7ba5fdb in pqxx::connection_base::close() () from /usr/lib/libpqxx-3.1.so
#1  0x0000000000401d3e in pqxx::basic_connection<pqxx::connect_direct>::~basic_connection (this=0x3,
    __in_chrg=<optimized out>) at /usr/include/pqxx/basic_connection.hxx:74
#2  0x0000000000401a3d in PGConnection::~PGConnection (this=0x7fffffffe600, __in_chrg=<optimized out>)
    at pgconnection.cpp:57
#3  0x00000000004026a3 in main () at main.cpp:11
(gdb) frame 2
#2  0x0000000000401a3d in PGConnection::~PGConnection (this=0x7fffffffe600, __in_chrg=<optimized out>)
    at pgconnection.cpp:57
57          delete conn;
(gdb) print conn
$1 = (pqxx::connection *) 0x3
(gdb)