diff --git a/src/unwind/unwind_with_winapi.cpp b/src/unwind/unwind_with_winapi.cpp
index d10f6d9..a499357 100644
--- a/src/unwind/unwind_with_winapi.cpp
+++ b/src/unwind/unwind_with_winapi.cpp
@@ -21,7 +21,7 @@ namespace detail {
     CPPTRACE_FORCE_NO_INLINE
     std::vector<frame_ptr> capture_frames(std::size_t skip, std::size_t max_depth) {
         std::vector<void*> addrs(skip + std::min(hard_max_frames, max_depth), nullptr);
-        int n_frames = CaptureStackBackTrace(
+        std::size_t n_frames = CaptureStackBackTrace(
             static_cast<ULONG>(skip + 1),
             static_cast<ULONG>(addrs.size()),
             addrs.data(),