diff --git a/src/rng/random.h b/src/rng/random.h
index 7652514..ee7c960 100644
--- a/src/rng/random.h
+++ b/src/rng/random.h
@@ -33,6 +33,6 @@ void random_bytes_free (const uint8_t *p);
 void random_get_salt (uint8_t *p);
 
 /* iterator returning a byta at a time */
-int random_gen (void *arg, unsigned char *output, size_t output_len);
+extern int random_gen (void *arg, unsigned char *output, size_t output_len);
 
 #endif
\ No newline at end of file