diff --git a/crypto.c b/crypto.c
index fc7c5d1d..4c1b7eec 100644
--- a/crypto.c
+++ b/crypto.c
@@ -117,7 +117,7 @@ _notmuch_crypto_get_gmime_context (_notmuch_crypto_t *crypto, const char *protoc
     return NULL;
 }
 
-int
+void
 _notmuch_crypto_cleanup (_notmuch_crypto_t *crypto)
 {
     if (crypto->gpgctx) {
@@ -129,12 +129,9 @@ _notmuch_crypto_cleanup (_notmuch_crypto_t *crypto)
 	g_object_unref (crypto->pkcs7ctx);
 	crypto->pkcs7ctx = NULL;
     }
-
-    return 0;
 }
 #else
-int _notmuch_crypto_cleanup (unused(_notmuch_crypto_t *crypto))
+void _notmuch_crypto_cleanup (unused(_notmuch_crypto_t *crypto))
 {
-    return 0;
 }
 #endif
diff --git a/notmuch-client.h b/notmuch-client.h
index 62acc70e..bdcfd893 100644
--- a/notmuch-client.h
+++ b/notmuch-client.h
@@ -185,7 +185,7 @@ GMimeCryptoContext *
 _notmuch_crypto_get_gmime_context (_notmuch_crypto_t *crypto, const char *protocol);
 #endif
 
-int
+void
 _notmuch_crypto_cleanup (_notmuch_crypto_t *crypto);
 
 int