diff --git a/libutils/ProcessCallStack.cpp b/libutils/ProcessCallStack.cpp
index 73ed4eb..983847c 100644
--- a/libutils/ProcessCallStack.cpp
+++ b/libutils/ProcessCallStack.cpp
@@ -21,6 +21,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include <memory>
 
 #include <utils/Log.h>