diff --git a/src/prng.c b/src/prng.c
index 8cb41eb..811ceae 100644
--- a/src/prng.c
+++ b/src/prng.c
@@ -29,6 +29,7 @@
 #include "prng.h"
 
 #include <errno.h>
+#include <inttypes.h>
 #include <string.h>
 
 #include <sys/random.h>
@@ -89,5 +90,8 @@ prng_seed (
     // as many bytes as requested.
     // This is guaranteed on both Linux and FreeBSD.
     debug_assert(nbytes == sizeof(state));
+    debug_printf("prng seed: "
+            "%016" PRIx64 "%016" PRIx64 "%016" PRIx64 "%016" PRIx64,
+            state[0], state[1], state[2], state[3]);
     return 0;
 }