From 9e5ef04dd42fb73a9bfe7bf712790000f09ed53d Mon Sep 17 00:00:00 2001
From: ferdymercury <ferdymercury@users.noreply.github.com>
Date: Mon, 7 Sep 2026 11:42:19 +0200
Subject: [PATCH] [core] deprecate Rstrstream.h

---
 README/ReleaseNotes/v642/index.md   |  1 +
 core/foundation/inc/Rstrstream.h    |  2 ++
 core/foundation/src/TClassEdit.cxx  |  8 ++++----
 core/rint/src/TTabCom.cxx           | 10 +++++-----
 tmva/tmva/src/GeneticPopulation.cxx |  4 +---
 5 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/README/ReleaseNotes/v642/index.md b/README/ReleaseNotes/v642/index.md
index 2cb3b828acc62..317fa53b195d1 100644
--- a/README/ReleaseNotes/v642/index.md
+++ b/README/ReleaseNotes/v642/index.md
@@ -76,6 +76,7 @@ The `TMVA_SOFIE_GNN` tutorials have been migrated to this workflow and produce i
 * The header `RStringView.h` deprecated in ROOT 6.14  will now emit warnings and will be fully removed after ROOT 6.44. Use `ROOT/RStringView.hxx` instead.
 * The header `snprintf.h` is deprecated (will emit warnings) and will be removed in ROOT 6.44. Use instead `<cstdio>`.
 * The header `Strlen.h` is deprecated and will be removed in ROOT 6.44. Use `<cstring>` directly as a replacement. `NEED_STRING` macro should not be defined or an error will be raised.
+* The header `Rstrstream.h` is deprecated and will be removed after ROOT 6.44, use instead `<sstream>`.
 
 ## Build System
 
diff --git a/core/foundation/inc/Rstrstream.h b/core/foundation/inc/Rstrstream.h
index 5562908f54a1e..4cbd0d1cbed51 100644
--- a/core/foundation/inc/Rstrstream.h
+++ b/core/foundation/inc/Rstrstream.h
@@ -12,6 +12,8 @@
 #ifndef ROOT_Rstrstream
 #define ROOT_Rstrstream
 
+#warning "This header is deprecated and will be removed after ROOT 6.44, used instead <sstream>"
+
 #include <ROOT/RConfig.hxx>
 
 #if defined(R__ANSISTREAM)
diff --git a/core/foundation/src/TClassEdit.cxx b/core/foundation/src/TClassEdit.cxx
index 9c2ccf48c6969..5607a62ad294b 100644
--- a/core/foundation/src/TClassEdit.cxx
+++ b/core/foundation/src/TClassEdit.cxx
@@ -12,13 +12,15 @@
  * For the list of contributors see $ROOTSYS/README/CREDITS.             *
  *************************************************************************/
 
+#include "TClassEdit.h"
+#include "TSpinLockGuard.h"
+
 #include <cstdio>
 #include <cstdlib>
 #include <cassert>
 #include <cstring>
-#include "TClassEdit.h"
 #include <cctype>
-#include "Rstrstream.h"
+#include <sstream>
 #include <set>
 #include <stack>
 // for shared_ptr
@@ -27,8 +29,6 @@
 #include <algorithm>
 #include <string>
 
-#include "TSpinLockGuard.h"
-
 using std::string, std::string_view, std::vector, std::set;
 
 namespace {
diff --git a/core/rint/src/TTabCom.cxx b/core/rint/src/TTabCom.cxx
index 8af741db377fb..466d2adf83eef 100644
--- a/core/rint/src/TTabCom.cxx
+++ b/core/rint/src/TTabCom.cxx
@@ -121,10 +121,6 @@
 //                                                                        //
 ////////////////////////////////////////////////////////////////////////////
 
-#include <cstdio>
-#include <cassert>
-#include <set>
-
 #include "RConfigure.h"
 #include "TTabCom.h"
 #include "TClass.h"
@@ -145,9 +141,13 @@
 #include "TMethodArg.h"
 #include "TInterpreter.h"
 #include "Riostream.h"
-#include "Rstrstream.h"
 #include "strlcpy.h"
 
+#include <cstdio>
+#include <cassert>
+#include <set>
+#include <sstream>
+
 #define BUF_SIZE 1024 // must be smaller than/equal to fgLineBufSize in Getline.cxx and
                       // lineBufSize in cppcompleter.py
 #define IfDebug(x)  if(gDebug==TTabCom::kDebug) x
diff --git a/tmva/tmva/src/GeneticPopulation.cxx b/tmva/tmva/src/GeneticPopulation.cxx
index fa7276aad9fa7..5482a98bdcab4 100644
--- a/tmva/tmva/src/GeneticPopulation.cxx
+++ b/tmva/tmva/src/GeneticPopulation.cxx
@@ -29,9 +29,6 @@ Population definition for genetic algorithm.
 
 */
 
-#include <algorithm>
-
-#include "Rstrstream.h"
 #include "TRandom3.h"
 #include "TH1.h"
 
@@ -39,6 +36,7 @@ Population definition for genetic algorithm.
 #include "TMVA/GeneticGenes.h"
 #include "TMVA/MsgLogger.h"
 
+#include <sstream>
 
 using std::vector, std::ostream;