Multithreaded Server in c++ : Memory leakage - c++

Question

I am writing a multithreaded server in c++(linux). My problem is that my code runs fine for initial few requests but after that it shows "free:Invalid pointer". I know this error can come from any part of my code but for the below snippet I want to know suggestions if I am going on right track.
// This is helper function used in pthread_create
void *Parse::serveRequest_helper(void *c)
{
Parse *P1 =(Parse *)c;
P1->serveRequest();
}
// On this function 10 threads are continously working
void Parse::serveRequest()
{
pthread_detach(pthread_self());
while(1)
{
pthread_mutex_lock(&print_lock);
if(requestqueue.empty())
pthread_cond_wait(&print_cond, &print_lock);
SendData *S = new SendData;
clientInfo c;
cout<<"Inside Serving thread"<<endl;
c = requestqueue.front(); //assuming this queue has data coming from some other scheduler thread function
requestqueue.pop();
S->requestPrint(c);
delete S;
pthread_mutex_unlock(&print_lock);
cout<<" Inside Thread is out"<<endl;
}
}
// Below function I am using to write data of the file to socket.
// When a thread will handle this function, the file pointer will be local to the thread or for all 10 threads it will be global .. ?
void SendData::requestPrint(clientInfo c)
{
if (write(c.accept,"Requested File Data :", 21) == -1)
perror("send");
ifstream file;
file.open(c.filename.c_str());
if (file.is_open())
{
string read;
while (!file.eof() )
{
getline(file,read);
if (write(c.accept, read.c_str(), (size_t)read.size()) == -1)
perror("send");
}
}
file.close();
close(c.accept);
}