diff --git a/.vscode/settings.json b/.vscode/settings.json
index adb4a79..11e5997 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -44,6 +44,7 @@
         "stdexcept": "cpp",
         "streambuf": "cpp",
         "cinttypes": "cpp",
-        "typeinfo": "cpp"
+        "typeinfo": "cpp",
+        "thread": "cpp"
     }
 }
\ No newline at end of file
diff --git a/lib/tcp_socket.hpp b/lib/tcp_socket.hpp
index cb12596..e38eac1 100644
--- a/lib/tcp_socket.hpp
+++ b/lib/tcp_socket.hpp
@@ -5,6 +5,7 @@
 #include <string>
 #include <vector>
 #include <thread>
+#include <mutex>
 #include <string.h>
 #include <arpa/inet.h>
 #include <netdb.h>
@@ -25,26 +26,19 @@ class client;
  * Server klasa za TCP/IP soket
  * Instanca se incijalizira kada pokrećemo server
 */
-// template<typename... Args>
-
 
 class server {
     public:
     int sock;
     struct sockaddr_in addr;
     SSL_CTX* securefds = NULL;
+    vector<thread> thr;
 
     server (const ushort port, const uint queue = 1000, SSL_CTX* _securefds = NULL);
     ~server ();
 
-    // one klijent
-    client* cli = NULL;
-    // template<typename... Args>
-    void sync(const uint timeout = 100, void (*func)(Args ...vars));   
-
-    // vector<thread> thr;
-    // vector<client*> clis;
-    // void async(const uint limit, void (*handlecli)(Args ...args) , const uint timeout = 100);
+    void sync(void (*handlecli)(client&), const uint timeout = 100);
+    void async(const uint limit, void (*handlecli)(client&, mutex&), const uint timeout = 100);
 
 };
 
diff --git a/src/tcp_socket.cpp b/src/tcp_socket.cpp
index 74467fb..90644b0 100644
--- a/src/tcp_socket.cpp
+++ b/src/tcp_socket.cpp
@@ -32,36 +32,42 @@ server::server (const ushort port, const uint queue, SSL_CTX* _securefds) {
 
 }
 
-template<typename... Args>
-void server::sync(const uint timeout, void (*func)(Args ...vars)) {
+/**
+ * Metoda za sinkroni rad s klijentima, prima pokazivač na funkciju i timeout;
+ * Funkcija handlecli prima referencu tipa client - važno za definiranje funkcija koje se šalju;
+ * Nije moguće proslijediti druge parametre;
+*/
+
+void server::sync(void (*handlecli)(client&), const uint timeout) {
     do {
-        if (cli != NULL) {
-            cli->~client();
-            cli = NULL;
-        }
-        cli = new client(this, timeout, securefds);
-        // callback
-        func();
+        client cli(this, timeout, securefds);
+        handlecli(cli);
     } while (true);
 }
 
-// template<typename... Args>
-// void server::async(const uint limit, void (*handlecli)(Args ...args), const uint timeout) {
-//     do {
-//         for (uint i=0; i<limit; i++) {
-//             clis.push_back(new client(this, timeout, securefds));
-//             thr.push_back(thread(handlecli, args...));
-//         }
+/**
+ * Metoda za asinkdorni rad s klijentima, prima limit, pokazivač na funkciju i timeout;
+ * Funkcija handlecli prima referencu tipa client - važno za definiranje funkcija koje se šalju;
+ * Nije moguće proslijediti druge parametre;
+*/
 
-//         for (uint i=0; i<limit; i++) {
-//             thr[i].join();
-//             clis[i]->~client();
-//         }
-//         thr.clear();
-//         clis.clear();
+void server::async(const uint limit, void (*handlecli)(client&, mutex&), const uint timeout) {
+    mutex io;
+    do {
+        for (uint i=0; i<limit; i++) {
+            thr.push_back(thread([&](){
+                client cli(this, timeout, securefds);
+                handlecli(cli, io);
+            }));
+        }
+
+        for (uint i=0; i<limit; i++) {
+            thr[i].join();
+        }
+        thr.clear();
 
-//     } while (true);
-// }
+    } while (true);
+}
 
 
 /**
@@ -71,9 +77,6 @@ void server::sync(const uint timeout, void (*func)(Args ...vars)) {
 
 server::~server () {
 
-    cli->~client();
-    cli = NULL;
-
     if (sock<=0) {
         throw string("[ERROR] The socket is already closed "); 
     }
diff --git a/test/server.cpp b/test/server.cpp
index d8c0eb6..58d0edc 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -41,19 +41,28 @@ int main() {
 
 
         server myserver(5000, 100);
-        // myserver.async(8, [](client *cli) {
-        //     cout << "Klijent " << cli->ipv4 << endl;
-        //     string fromclient = cli->pull();
-        //     cout << "S klijenta " << fromclient << endl;
-        //     cli->push(fromclient);
-        // }, 200);
-        myserver.sync(8, [](client *cli) {
-            cout << "Klijent " << cli->ipv4 << endl;
-            string fromclient = cli->pull();
+        myserver.async(8, [](client &cli, mutex &io) {
+            cout << "Klijent " << cli.ipv4 << endl;
+            string fromclient = cli.pull();
+            io.lock();
             cout << "S klijenta " << fromclient << endl;
-            cli->push(fromclient);
+            io.unlock();
+            // fromclient += teststr;
+            cli.push(fromclient);
         }, 200);
 
+        // string teststr = " Idemooo";
+
+        // myserver.sync([](client &cli, mutex &io) {
+        //     cout << "Klijent " << cli.ipv4 << endl;
+        //     string fromclient = cli.pull();
+        //     io.lock();
+        //     cout << "S klijenta " << fromclient << endl;
+        //     io.unlock();
+        //     // fromclient += teststr;
+        //     cli.push(fromclient);
+        // });
+
     }
     catch(const string err) {
         cout << err << endl;
diff --git a/test/server.o b/test/server.o
index 5a4e551..65bc4f7 100755
Binary files a/test/server.o and b/test/server.o differ