diff --git a/dcapi/boinc/client.C b/dcapi/boinc/client.C
index daba92e1c3..ac2172ebae 100644
--- a/dcapi/boinc/client.C
+++ b/dcapi/boinc/client.C
@@ -16,6 +16,7 @@
 #include <string.h>
 #include <limits.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #ifndef _WIN32
 #include <dirent.h>