diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 4b09f24..a80965f 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -19,6 +19,7 @@
 
 #include <assert.h>
 #include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdbool.h>