From cdd8dee205290c45b28f8c00aaefe06e30d60e8f Mon Sep 17 00:00:00 2001
From: Stephen Webb <swebb2066@gmail.com>
Date: Fri, 2 Aug 2024 12:56:22 +1000
Subject: [PATCH 1/2] Add a diagnostic hint to input stream error

---
 include/boost/archive/basic_text_iprimitive.hpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/boost/archive/basic_text_iprimitive.hpp b/include/boost/archive/basic_text_iprimitive.hpp
index 606f59f580..2546017070 100644
--- a/include/boost/archive/basic_text_iprimitive.hpp
+++ b/include/boost/archive/basic_text_iprimitive.hpp
@@ -26,6 +26,7 @@
 
 #include <locale>
 #include <cstddef> // size_t
+#include <cstdlib> // itoa
 
 #include <boost/config.hpp>
 #if defined(BOOST_NO_STDC_NAMESPACE)
@@ -86,10 +87,13 @@ class BOOST_SYMBOL_VISIBLE basic_text_iprimitive {
     template<class T>
     void load(T & t)
     {
+        auto pos = is.tellg();
         if(is >> t)
             return;
+        static char at_offset[64] = "at offset ";
+        itoa(pos, &at_offset[10], 10);
         boost::serialization::throw_exception(
-            archive_exception(archive_exception::input_stream_error)
+            archive_exception(archive_exception::input_stream_error, at_offset)
         );
     }
 

From 87e19651beb09fbde0c019c8e881731bb4ef904f Mon Sep 17 00:00:00 2001
From: Stephen Webb <swebb2066@gmail.com>
Date: Thu, 30 Jul 2026 14:48:24 +1000
Subject: [PATCH 2/2] Use snprintf instead of itoa

---
 include/boost/archive/basic_text_iprimitive.hpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/boost/archive/basic_text_iprimitive.hpp b/include/boost/archive/basic_text_iprimitive.hpp
index 2546017070..50c66f5d4a 100644
--- a/include/boost/archive/basic_text_iprimitive.hpp
+++ b/include/boost/archive/basic_text_iprimitive.hpp
@@ -26,7 +26,7 @@
 
 #include <locale>
 #include <cstddef> // size_t
-#include <cstdlib> // itoa
+#include <stdio.h> // snprintf
 
 #include <boost/config.hpp>
 #if defined(BOOST_NO_STDC_NAMESPACE)
@@ -90,11 +90,14 @@ class BOOST_SYMBOL_VISIBLE basic_text_iprimitive {
         auto pos = is.tellg();
         if(is >> t)
             return;
-        static char at_offset[64] = "at offset ";
-        itoa(pos, &at_offset[10], 10);
+        char at_offset[64] = "at offset ";
+        if (std::streampos(-1) == pos)
+            snprintf&at_offset[10], 54, "%s", "<unknown>");
+        else
+            snprintf(&at_offset[10], 54, "%d", static_cast<std::streamoff>(pos));
         boost::serialization::throw_exception(
             archive_exception(archive_exception::input_stream_error, at_offset)
-        );
+            );
     }
 
     void load(char & t)