1 files changed, 6 insertions, 0 deletions
diff --git a/c/sha3.h b/c/sha3.h
index 99cd209..6587795 100644
--- a/c/sha3.h
+++ b/c/sha3.h
@@ -16,6 +16,9 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#ifndef __SHA3_H__
+#define __SHA3_H__
+
 #include <stdlib.h>
 
 
@@ -106,3 +109,6 @@ extern byte* sha3_squeeze(void);
  */
 extern llong* sha3_state(void);
 
+
+#endif
+