diff --git a/Examples/Monocular/mono_euroc.cc b/Examples/Monocular/mono_euroc.cc
index 4bcb90f170..997fe6151d 100644
--- a/Examples/Monocular/mono_euroc.cc
+++ b/Examples/Monocular/mono_euroc.cc
@@ -18,6 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/Examples/Monocular/mono_kitti.cc b/Examples/Monocular/mono_kitti.cc
index f2f7b3ebfd..25ffdca12d 100644
--- a/Examples/Monocular/mono_kitti.cc
+++ b/Examples/Monocular/mono_kitti.cc
@@ -18,6 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/Examples/Monocular/mono_tum.cc b/Examples/Monocular/mono_tum.cc
index 09a2afc4b7..986ce6f746 100644
--- a/Examples/Monocular/mono_tum.cc
+++ b/Examples/Monocular/mono_tum.cc
@@ -18,6 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/Examples/RGB-D/rgbd_tum.cc b/Examples/RGB-D/rgbd_tum.cc
index 001199d1aa..4acb0e9189 100644
--- a/Examples/RGB-D/rgbd_tum.cc
+++ b/Examples/RGB-D/rgbd_tum.cc
@@ -17,7 +17,7 @@
 * You should have received a copy of the GNU General Public License
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
-
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/Examples/ROS/ORB_SLAM2/CMakeLists.txt b/Examples/ROS/ORB_SLAM2/CMakeLists.txt
index 7cbf71c199..b17cf933a6 100644
--- a/Examples/ROS/ORB_SLAM2/CMakeLists.txt
+++ b/Examples/ROS/ORB_SLAM2/CMakeLists.txt
@@ -40,6 +40,7 @@ endif()
 
 find_package(Eigen3 3.1.0 REQUIRED)
 find_package(Pangolin REQUIRED)
+find_package(Boost COMPONENTS system REQUIRED)
 
 include_directories(
 ${PROJECT_SOURCE_DIR}
@@ -55,6 +56,7 @@ ${Pangolin_LIBRARIES}
 ${PROJECT_SOURCE_DIR}/../../../Thirdparty/DBoW2/lib/libDBoW2.so
 ${PROJECT_SOURCE_DIR}/../../../Thirdparty/g2o/lib/libg2o.so
 ${PROJECT_SOURCE_DIR}/../../../lib/libORB_SLAM2.so
+${Boost_SYSTEM_LIBRARY}
 )
 
 # Node for monocular camera
diff --git a/Examples/Stereo/stereo_euroc.cc b/Examples/Stereo/stereo_euroc.cc
index 6bc09c50be..6de6b15996 100644
--- a/Examples/Stereo/stereo_euroc.cc
+++ b/Examples/Stereo/stereo_euroc.cc
@@ -17,7 +17,7 @@
 * You should have received a copy of the GNU General Public License
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
-
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/Examples/Stereo/stereo_kitti.cc b/Examples/Stereo/stereo_kitti.cc
index cb8bc4096e..a9465110f6 100644
--- a/Examples/Stereo/stereo_kitti.cc
+++ b/Examples/Stereo/stereo_kitti.cc
@@ -17,7 +17,7 @@
 * You should have received a copy of the GNU General Public License
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
-
+#include <unistd.h>
 
 #include<iostream>
 #include<algorithm>
diff --git a/src/LocalMapping.cc b/src/LocalMapping.cc
index 6c87a6e55a..25730ec502 100644
--- a/src/LocalMapping.cc
+++ b/src/LocalMapping.cc
@@ -18,6 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
 #include "LocalMapping.h"
 #include "LoopClosing.h"
 #include "ORBmatcher.h"
diff --git a/src/LoopClosing.cc b/src/LoopClosing.cc
index 5e317dd420..8bc9e51876 100644
--- a/src/LoopClosing.cc
+++ b/src/LoopClosing.cc
@@ -17,6 +17,7 @@
 * You should have received a copy of the GNU General Public License
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
+#include <unistd.h>
 
 #include "LoopClosing.h"
 
diff --git a/src/System.cc b/src/System.cc
index 8df4157095..1024507d8a 100644
--- a/src/System.cc
+++ b/src/System.cc
@@ -18,7 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
-
+#include <unistd.h>
 
 #include "System.h"
 #include "Converter.h"
diff --git a/src/Tracking.cc b/src/Tracking.cc
index 2273b2ce48..2515b1f16c 100644
--- a/src/Tracking.cc
+++ b/src/Tracking.cc
@@ -18,6 +18,7 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
 
 #include "Tracking.h"
 
diff --git a/src/Viewer.cc b/src/Viewer.cc
index dec3204f53..da325d0566 100644
--- a/src/Viewer.cc
+++ b/src/Viewer.cc
@@ -18,6 +18,8 @@
 * along with ORB-SLAM2. If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <unistd.h>
+
 #include "Viewer.h"
 #include <pangolin/pangolin.h>