diff --git a/lib/cpp/src/transport/TSSLSocket.cpp b/lib/cpp/src/transport/TSSLSocket.cpp
index f84f806..5e18e94 100644
--- a/lib/cpp/src/transport/TSSLSocket.cpp
+++ b/lib/cpp/src/transport/TSSLSocket.cpp
@@ -478,7 +478,7 @@
 
 #if (OPENSSL_VERSION_NUMBER < OPENSSL_VERSION_NO_THREAD_ID)
 static unsigned long callbackThreadID() {
-  return reinterpret_cast<unsigned long>(pthread_self());
+  return (unsigned long) pthread_self();
 }
 #endif