Ошибка двойного освобождения или повреждения — valgrind

Моя программа выходит когда main Функция пытается запустить какой-то класс (Rock) более одного раза с double free or corruption ошибка glibc.

Valgrind возвращает:

==18672== Conditional jump or move depends on uninitialised value(s)
==18672==    at 0x56F8554: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_int<unsigned long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/libstdc++.so.6.0.17)
==18672==    by 0x56F876C: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/libstdc++.so.6.0.17)
==18672==    by 0x56FB945: std::ostream& std::ostream::_M_insert<unsigned long>(unsigned long) (in /usr/lib64/libstdc++.so.6.0.17)
==18672==    by 0x431515: Rock::saveClustering(std::set<Attribution, std::less<Attribution>, std::allocator<Attribution> >) (rock.cpp:1406)
==18672==    by 0x430C66: Rock::startRock() (rock.cpp:1321)
==18672==    by 0x45DABC: main (main.cpp:207)
==18672==  Uninitialised value was created by a stack allocation
==18672==    at 0x42FF39: Rock::getFinalList(std::vector<Rock::BestLabel, std::allocator<Rock::BestLabel> >&) (rock.cpp:1139)
==18672==
==18672==
==18672== HEAP SUMMARY:
==18672==     in use at exit: 292 bytes in 11 blocks
==18672==   total heap usage: 86,558 allocs, 86,547 frees, 21,133,326 bytes allocated
==18672==
==18672== 292 (52 direct, 240 indirect) bytes in 1 blocks are definitely lost in loss record 11 of 11
==18672==    at 0x4C2BCFB: malloc (vg_replace_malloc.c:270)
==18672==    by 0x5F7FC94: nss_parse_service_list (in /lib64/libc-2.15.so)
==18672==    by 0x5F80173: __nss_database_lookup (in /lib64/libc-2.15.so)
==18672==    by 0xC1C15DB: ???
==18672==    by 0x5F3592B: getpwuid_r@@GLIBC_2.2.5 (in /lib64/libc-2.15.so)
==18672==    by 0x5050638: pqGetpwuid (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503C3BD: pqGetHomeDirectory (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503CCD4: getPgPassFilename (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503F78A: PasswordFromFile (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503FAAB: connectOptions2 (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503FD77: PQconnectStart (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==    by 0x503FDA5: PQconnectdb (in /opt/postgres_home/lib/libpq.so.5.3)
==18672==
==18672== LEAK SUMMARY:
==18672==    definitely lost: 52 bytes in 1 blocks
==18672==    indirectly lost: 240 bytes in 10 blocks
==18672==      possibly lost: 0 bytes in 0 blocks
==18672==    still reachable: 0 bytes in 0 blocks
==18672==         suppressed: 0 bytes in 0 blocks

Я не привык к Вальгрингу. Говорит ли он, что была единичная память, которая не была свободна в отношении postgres доступ к базе данных? Метод, который я использовал для получения данных:

void Comum::fetchDB ( string sql_statement )
{
string conn_str ( "dbname=" + getDbName() + " user=" + getDbUser() );
pqxx::connection conn (conn_str);
pqxx::work txn (conn);              // ex: domain = "voice"pqxx::result r = txn.exec (sql_statement);

if ( r.size () == 0 ) {
std::cerr << "No records found for '" << domain << "'." << endl;
exit (12);
}

txn.commit ();

for (unsigned int u = 0; u != getNrFields (); ++u) {
vector <string> v;
v.reserve (r.size());
db_fetched.push_back (v);
}

for (unsigned int rownum = 0; rownum != r.size(); ++rownum) {
const pqxx::result::tuple row = r[rownum];

for (unsigned int colnum = 0; colnum != row.size(); ++colnum) {
const pqxx::result::field f = row[colnum];
db_fetched [colnum].push_back( f.c_str() );
}
}
conn.disconnect();
}

Относительно первой строки вывода Вальгринда Conditional jump or move depends on unitialized value(s) saveClusteringМетод выглядит следующим образом:

void Rock::saveClustering (const set<Attribution> result)
{
string rock_dir = "rock";
string parent_dir = "output";
string dir = parent_dir + "/" + rock_dir;

// Create directory.
createDir (parent_dir);
createDir (dir);

// Build filename.
string filename;

map<unsigned int, AttType>::const_iterator citype = att_type.begin();
while (citype != att_type.end()) {
filename += citype->second.getName();
if (++citype != att_type.end()) {
filename += "-";
}
}

filename = parent_dir + "/" + rock_dir + "/" + filename + "-" + currentDateTime() + ".txt";
ofstream myfile(filename.c_str());

if (myfile.is_open()) {
for ( set<Attribution>::const_iterator ci = result.begin();ci != result.end(); ++ci ) {
myfile << ci->id << "\t";

for (vector<unsigned int>::const_iterator enci = ci->encodings.begin(); enci != ci->encodings.end(); ++enci) {
myfile << *enci << "\t";
}

myfile << ci->type << "\t" << ci->assignment << endl;  // 1406 LINE
}
myfile << endl;
myfile.close();

} else {
cerr << "It was not possible to save decoder filename " << filename << endl;
cerr << "Press any key <ENTER> to continue.";
}
}

Я просто не вижу, что не так, и не могу представить небольшую работоспособную программу.