diff --git a/src/zimlib/include/zim/fstream.h b/src/zimlib/include/zim/fstream.h
index be9f161..133cc70 100644
--- a/src/zimlib/include/zim/fstream.h
+++ b/src/zimlib/include/zim/fstream.h
@@ -66,7 +66,7 @@ namespace zim
       std::streambuf::int_type underflow();
       int sync();
 
-      void setCurrentFile(const std::string& fname, off_t off);
+      void setCurrentFile(const std::string& fname, zim::offset_type off);
 
     public:
       streambuf(const std::string& fname, unsigned bufsize, unsigned openFilesCache);