diff --git a/particle.c b/particle.c
index 468bd28..1b06f9a 100644
--- a/particle.c
+++ b/particle.c
@@ -5,6 +5,7 @@
 #include <unistd.h>
 #include <assert.h>
 #include <errno.h>
+#include <signal.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>