diff --git a/vendor/bcrypt/bcrypt.c b/vendor/bcrypt/bcrypt.c
index cb0632a..60448b7 100644
--- a/vendor/bcrypt/bcrypt.c
+++ b/vendor/bcrypt/bcrypt.c
@@ -54,7 +54,7 @@ static int try_close(int fd)
 static int try_read(int fd, char *out, size_t count)
 {
 	size_t total;
-	ssize_t partial;
+	__int64 partial;
 
 	total = 0;
 	while (total < count)