diff --git a/src/epub2txt.c b/src/epub2txt.c
index 8cfefac..47d41d3 100644
--- a/src/epub2txt.c
+++ b/src/epub2txt.c
@@ -12,6 +12,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <signal.h>
 #include <errno.h>
 #ifndef __APPLE__
 #include <malloc.h>