diff --git a/src/vm.c b/src/vm.c
index df4ce97..a9354bc 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -24,6 +24,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <unistd.h>
 #include "cpu.h"
 
 // Load program from file