diff --git a/src/dictd_parser.cpp b/src/dictd_parser.cpp
--- a/src/dictd_parser.cpp
+++ b/src/dictd_parser.cpp
@@ -26,6 +26,7 @@
 #include <cerrno>
 #include <cstring>
 #include <cstdio>
+#include <cstdlib>
 #include <glib/gi18n.h>
 #include <vector>
 
diff --git a/src/parser.cpp b/src/parser.cpp
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -28,6 +28,7 @@
 
 #include <glib/gi18n.h>
 #include <glib.h>
+#include <cstdlib>
 
 #include "utils.hpp"
 #include "resource.hpp"
diff --git a/src/process.hpp b/src/process.hpp
--- a/src/process.hpp
+++ b/src/process.hpp
@@ -2,6 +2,7 @@
 #define __PROCESS_HPP__
 
 #include <glib.h>
+#include <cstdlib>
 #include <string>
 
 #include "file.hpp"