diff --git a/cbits/conv.c b/cbits/conv.c
--- a/cbits/conv.c
+++ b/cbits/conv.c
@@ -11,6 +11,7 @@
 #define THREAD_SAFE 0
 #endif
 
+#include <string.h>
 #include <time.h>
 #include <locale.h>
 
@@ -35,6 +36,7 @@
 time_t c_parse_unix_time(char *fmt, char *src) {
     struct tm dst;
     init_locale();
+    memset(&dst, 0, sizeof(struct tm));
 #if THREAD_SAFE
     strptime_l(src, fmt, &dst, c_locale);
 #else
@@ -46,6 +48,7 @@
 time_t c_parse_unix_time_gmt(char *fmt, char *src) {
     struct tm dst;
     init_locale();
+    memset(&dst, 0, sizeof(struct tm));
 #if THREAD_SAFE
     strptime_l(src, fmt, &dst, c_locale);
 #else
diff --git a/unix-time.cabal b/unix-time.cabal
--- a/unix-time.cabal
+++ b/unix-time.cabal
@@ -1,5 +1,5 @@
 Name:                   unix-time
-Version:                0.1.4
+Version:                0.1.5
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -25,8 +25,9 @@
                       , old-time
   C-Sources:            cbits/conv.c
 
-Test-Suite doctests
+Test-Suite doctest
   Type:                 exitcode-stdio-1.0
+  Default-Language:     Haskell2010
   HS-Source-Dirs:       test
   Ghc-Options:          -threaded -Wall
   Main-Is:              doctests.hs