From 3f6d6f41e0d7a8ffd8969a1d63d636ed0ee17d56 Mon Sep 17 00:00:00 2001
From: mborgerding <mark@borgerding.net>
Date: Mon, 24 Aug 2026 08:53:27 -0400
Subject: [PATCH] avoid undefined behavior:

calling `front()` on a possibly empty `std::vector` crashes systems that use debug checks.
See github issue #526

https://github.com/boostorg/python/issues/526
---
 src/numpy/ndarray.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/numpy/ndarray.cpp b/src/numpy/ndarray.cpp
index af09ecc338..9217753932 100644
--- a/src/numpy/ndarray.cpp
+++ b/src/numpy/ndarray.cpp
@@ -127,8 +127,8 @@ ndarray from_data_impl(void * data,
     (PyArray_NewFromDescr(&PyArray_Type,
 			  incref_dtype(dt),
 			  shape.size(),
-			  const_cast<Py_intptr_t*>(&shape.front()),
-			  const_cast<Py_intptr_t*>(&strides.front()),
+			  const_cast<Py_intptr_t*>(shape.data()),
+			  const_cast<Py_intptr_t*>(strides.data()),
 			  data,
 			  flags,
 			  NULL)));