From f6425d7773b417be91f56c951a5a591dd49dce9f Mon Sep 17 00:00:00 2001
From: Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
Date: Sat, 11 Oct 2025 14:57:17 +0200
Subject: [PATCH] write error message only once

---
 .../include/CGAL/Linear_cell_complex/IO/VTK.h             | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Linear_cell_complex/include/CGAL/Linear_cell_complex/IO/VTK.h b/Linear_cell_complex/include/CGAL/Linear_cell_complex/IO/VTK.h
index a5700661597..ab829bf5b8d 100644
--- a/Linear_cell_complex/include/CGAL/Linear_cell_complex/IO/VTK.h
+++ b/Linear_cell_complex/include/CGAL/Linear_cell_complex/IO/VTK.h
@@ -22,6 +22,7 @@
 #include <string>
 #include <unordered_map>
 #include <vector>
+#include <set>
 
 namespace CGAL {
 namespace IO {
@@ -361,6 +362,7 @@ bool read_lcc_from_vtk_ascii(std::istream& is, LCC& alcc,
 
   // Create cells based on types
   std::size_t cell_type;
+  std::set<std::size_t> error_types;
   for(std::size_t i = 0; i<ncells; ++i)
   {
     if(!(is>>cell_type))
@@ -408,7 +410,11 @@ bool read_lcc_from_vtk_ascii(std::istream& is, LCC& alcc,
       make_generic_cell_with_builder(ib, v);
       break;
     default:
-      std::cerr<<"[ERROR] read_VTK: type "<<cell_type<<" unknown."<<std::endl;
+      if(error_types.count(cell_type)==0)
+      {
+        std::cerr<<"[ERROR] read_VTK: type "<<cell_type<<" unknown."<<std::endl;
+        error_types.insert(cell_type);
+      }
     }
   }