pointer difference type

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
 
-set(BLT_VERSION 0.17.11)
+set(BLT_VERSION 0.17.12)
 set(BLT_TEST_VERSION 0.0.1)
 
 set(BLT_TARGET BLT)

include/blt/std/types.h

@@ -37,6 +37,7 @@ namespace blt
     using u64 = std::uint64_t;
     
     using size_t = std::size_t;
+    using ptrdiff_t = std::ptrdiff_t;
     using f32 = float;
     using f64 = double;
 #ifndef NO_BLT_NAMESPACE_ON_TYPES