diff --git a/libmaxsi/c/hsrc/sys/types.h b/libmaxsi/c/hsrc/sys/types.h
index 46abb15e..3c9d888b 100644
--- a/libmaxsi/c/hsrc/sys/types.h
+++ b/libmaxsi/c/hsrc/sys/types.h
@@ -32,6 +32,7 @@
 __BEGIN_DECLS
 
 @include(useconds_t.h)
+@include(pid_t.h)
 
 __END_DECLS