--- a/src/etherStreambuf.cpp
+++ b/src/etherStreambuf.cpp
@@ -28,6 +28,7 @@
 #include "etherStreambuf.h"
 
 #include <stdio.h>
+#include <unistd.h>
 
 namespace tc {
    etherStreambuf::etherStreambuf() {
--- a/src/tcStreambuf.cpp
+++ b/src/tcStreambuf.cpp
@@ -30,6 +30,7 @@
 // this is for the udp-part...
 #include <netdb.h>         // gethostbyname hostent
 #include <arpa/inet.h>     // inet_ntoa
+#include <unistd.h>
 
 namespace tc {
    char tcStreambuf::tcPktType::confirmation(char pktType) {