diff --git a/src/Configfile.cpp.in b/src/Configfile.cpp.in
index ad3da37..c433de4 100644
--- a/src/Configfile.cpp.in
+++ b/src/Configfile.cpp.in
@@ -19,6 +19,8 @@
  */
 #include "Configfile.h"
 
+#include <unistd.h>
+
 extern LOGGER_CLASS hermes_log;
 
 /**
diff --git a/src/Database.cpp b/src/Database.cpp
index dc10935..bd2c723 100644
--- a/src/Database.cpp
+++ b/src/Database.cpp
@@ -19,6 +19,7 @@
  */
 #include "Database.h"
 
+#include <unistd.h>
 extern LOGGER_CLASS hermes_log;
 
 void Database::setDatabaseFile(string p_dbfile)
diff --git a/src/Database.h b/src/Database.h
index 9f0b01d..f14ead6 100644
--- a/src/Database.h
+++ b/src/Database.h
@@ -22,6 +22,7 @@
 
 #include "hermes.h"
 
+#include <stdlib.h>
 #include <iostream>
 #include <string>
 #include <sqlite3.h>
diff --git a/src/Socket.cpp b/src/Socket.cpp
index d5aac52..36c5c97 100644
--- a/src/Socket.cpp
+++ b/src/Socket.cpp
@@ -18,6 +18,7 @@
  * @author Juan José Gutiérrez de Quevedo <juanjo@gutierrezdequevedo.com>
  */
 #include "Socket.h"
+#include <unistd.h>
 
 int Socket::created_sockets=0;
 
diff --git a/src/Utils.cpp b/src/Utils.cpp
index a3ea25e..95504dc 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -19,6 +19,8 @@
  */
 #include "Utils.h"
 
+#include <unistd.h>
+
 extern Configfile cfg;
 extern LOGGER_CLASS hermes_log;