diff --git a/voice_processing/voice_processing.c b/voice_processing/voice_processing.c
index d2b4acb..8c6e7fc 100644
--- a/voice_processing/voice_processing.c
+++ b/voice_processing/voice_processing.c
@@ -18,6 +18,8 @@
 /*#define LOG_NDEBUG 0*/
 #include <stdlib.h>
 #include <dlfcn.h>
+#include <unistd.h>
+
 #include <cutils/log.h>
 #include <cutils/list.h>
 #include <hardware/audio_effect.h>