1 files changed, 5 insertions, 0 deletions
diff --git a/siphash.h b/siphash.h
index 5578586..80208ee 100644
--- a/siphash.h
+++ b/siphash.h
@@ -3,8 +3,13 @@
  * Author: Stefano Brivio <sbrivio@redhat.com>
  */
 
+#ifndef SIPHASH_H
+#define SIPHASH_H
+
 uint64_t siphash_8b(const uint8_t *in, const uint64_t *k);
 uint32_t siphash_12b(const uint8_t *in, const uint64_t *k);
 uint64_t siphash_20b(const uint8_t *in, const uint64_t *k);
 uint32_t siphash_32b(const uint8_t *in, const uint64_t *k);
 uint32_t siphash_36b(const uint8_t *in, const uint64_t *k);
+
+#endif /* SIPHASH_H */