From 252708e38992852b6d3be690eef0dbfb6eb0452c Mon Sep 17 00:00:00 2001
From: conrad <conrad@localhost.localdomain>
Date: Fri, 20 Feb 2026 13:17:43 +1000
Subject: [PATCH] get pointer to first element via dedicated function

---
 include/armadillo_bits/subview_bones.hpp |  3 +++
 include/armadillo_bits/subview_meat.hpp  | 28 ++++++++++++++++++++----
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/include/armadillo_bits/subview_bones.hpp b/include/armadillo_bits/subview_bones.hpp
index f3837606..4f727737 100644
--- a/include/armadillo_bits/subview_bones.hpp
+++ b/include/armadillo_bits/subview_bones.hpp
@@ -142,6 +142,9 @@ class subview : public Base< eT, subview<eT> >
   arma_inline       eT* colptr(const uword in_col);
   arma_inline const eT* colptr(const uword in_col) const;
   
+  arma_inline       eT* startptr();
+  arma_inline const eT* startptr() const;
+  
   template<typename eT2>
   inline bool check_overlap(const subview<eT2>& x) const;
   
diff --git a/include/armadillo_bits/subview_meat.hpp b/include/armadillo_bits/subview_meat.hpp
index 487924aa..4135dff8 100644
--- a/include/armadillo_bits/subview_meat.hpp
+++ b/include/armadillo_bits/subview_meat.hpp
@@ -1425,6 +1425,26 @@ subview<eT>::colptr(const uword in_col) const
 
 
 
+template<typename eT>
+arma_inline
+eT*
+subview<eT>::startptr()
+  {
+  return (m.mem == nullptr) ? nullptr : ( & access::rw((const_cast< Mat<eT>& >(m)).mem[ aux_col1*m.n_rows + aux_row1 ]) );
+  }
+
+
+
+template<typename eT>
+arma_inline
+const eT*
+subview<eT>::startptr() const
+  {
+  return (m.mem == nullptr) ? nullptr : ( & m.mem[ aux_col1*m.n_rows + aux_row1 ] );
+  }
+
+
+
 template<typename eT>
 template<typename eT2>
 inline
@@ -3266,7 +3286,7 @@ template<typename eT>
 inline
 subview_col<eT>::subview_col(const Mat<eT>& in_m, const uword in_col)
   : subview<eT>(in_m, 0, in_col, in_m.n_rows, 1)
-  , colmem(subview<eT>::colptr(0)) 
+  , colmem(subview<eT>::startptr()) 
   {
   arma_debug_sigprint();
   }
@@ -3277,7 +3297,7 @@ template<typename eT>
 inline
 subview_col<eT>::subview_col(const Mat<eT>& in_m, const uword in_col, const uword in_row1, const uword in_n_rows)
   : subview<eT>(in_m, in_row1, in_col, in_n_rows, 1)
-  , colmem(subview<eT>::colptr(0)) 
+  , colmem(subview<eT>::startptr()) 
   {
   arma_debug_sigprint();
   }
@@ -4270,7 +4290,7 @@ template<typename eT>
 inline
 subview_row<eT>::subview_row(const Mat<eT>& in_m, const uword in_row)
   : subview<eT>(in_m, in_row, 0, 1, in_m.n_cols)
-  , rowmem(subview<eT>::colptr(0))
+  , rowmem(subview<eT>::startptr())
   {
   arma_debug_sigprint();
   }
@@ -4281,7 +4301,7 @@ template<typename eT>
 inline
 subview_row<eT>::subview_row(const Mat<eT>& in_m, const uword in_row, const uword in_col1, const uword in_n_cols)
   : subview<eT>(in_m, in_row, in_col1, 1, in_n_cols)
-  , rowmem(subview<eT>::colptr(0))
+  , rowmem(subview<eT>::startptr())
   {
   arma_debug_sigprint();
   }