It sometimes stucks on beginning

Makefile

@@ -2,7 +2,7 @@ EXECUTABLE = server
 EXECUTABLECLI = client
 
 CC=g++ -lboost_system -lboost_thread
-CFLAGS=-Wall -O2 -DDEBUG -Wreorder
+CFLAGS=-Wall -DDEBUG -Wreorder
 COMPILE=$(CC) $(CFLAGS)
 
 all: server client

client.cpp

@@ -44,7 +44,7 @@ void Sender()
             lock_guard<mutex> lock(WriteReadMutex);
             len+=SSL_write(SSLHandler, buf.c_str()+len, buf.size()-len);
             // for debugging re-neg
-            // cout << "SSL STATE: " << SSL_state_string(handler.second) << endl;
+            cout << "SSL STATE: " << SSL_state_string(SSLHandler) << endl;
         } while( len != static_cast<int>(buf.size()) );
     }
 };
@@ -52,6 +52,7 @@ void Sender()
 void Client::receive()
 {
     char buf[MAX_PACKET_SIZE];
+    cout << "R " << endl;
 
     // TODO: this way it takes 100% CPU, some signal would be usefull
     memset(buf,'\0',MAX_PACKET_SIZE);
@@ -97,6 +98,13 @@ void Client::connect()
     }
 
     SSLHandler = SSL_new(_ctx);
+
+    long mode = SSL_CTX_set_mode(_ctx, SSL_MODE_AUTO_RETRY);
+    if( ( mode & SSL_MODE_AUTO_RETRY) != SSL_MODE_AUTO_RETRY )
+    {
+        throw runtime_error("SSL_MODE_AUTO_RETRY couldn't be set");
+    }
+
     SSL_set_fd(SSLHandler, _handler);
 
     if( SSL_connect(SSLHandler) <= 0)
@@ -105,7 +113,9 @@ void Client::connect()
         exit(1);
     }
 //    bug reproduces even if call is blocking, so not need to uncommet this line
-//    fcntl(_handler, F_SETFL, O_NONBLOCK);
+    int opts = fcntl(_handler,F_GETFL);
+    opts = opts & ( ~O_NONBLOCK );
+    fcntl(_handler, F_SETFL, opts);
 }
 
 void Client::start()