diff --git a/src/options.cpp b/src/options.cpp
index e4bc011a..c89d3a02 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -285,13 +285,13 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
 
         case ZMQ_TCP_RECV_BUFFER:
             if (is_int && (value >= 0 && value <= 10) ) {
-                tcp_recv_buffer_size = static_cast<int>(std::pow(2, value)) * 1024;
+                tcp_recv_buffer_size = static_cast<unsigned int>(std::pow(2.0, value)) * 1024;
             }
             break;
 
         case ZMQ_TCP_SEND_BUFFER:
             if (is_int && (value >= 0 && value <= 10) ) {
-                tcp_send_buffer_size = static_cast<int>(std::pow(2, value)) * 1024;
+                tcp_send_buffer_size = static_cast<unsigned int>(std::pow(2.0, value)) * 1024;
             }
             break;
 
diff --git a/src/options.hpp b/src/options.hpp
index be04ec64..5eab5060 100644
--- a/src/options.hpp
+++ b/src/options.hpp
@@ -156,9 +156,9 @@ namespace zmq
         typedef std::vector <tcp_address_mask_t> tcp_accept_filters_t;
         tcp_accept_filters_t tcp_accept_filters;
 
-        // TCO buffer sizes
-        int tcp_recv_buffer_size;
-        int tcp_send_buffer_size;
+        // TCP buffer sizes
+        unsigned int tcp_recv_buffer_size;
+        unsigned int tcp_send_buffer_size;
 
         // IPC accept() filters
 #       if defined ZMQ_HAVE_SO_PEERCRED || defined ZMQ_HAVE_LOCAL_PEERCRED