whats-new-cpp-docs.md

title	ms.date	description	ms.custom	monikerRange
What's new for the C++ docs	08/22/2023	The new docs and doc updates for the Microsoft C/C++ compiler, ATL/MFC, C runtime, and standard library docs.	intro-whats-new	>=msvc-160

Microsoft C++ docs: What's new for May 2023 to August 2023

This article lists major changes to the Microsoft C++ docs May 2023 through August 2023. These changes correspond approximately to Visual Studio version 17.7.

• For what was new in the docs in previous months, see What's new history.
• For what's new related to C++ in Visual Studio, see What's new for C++ in Visual Studio.
• For the latest C and C++ conformance with ISO standards status, see C++ conformance improvements in Visual Studio.

Active Template Library (ATL), Microsoft Foundation Classes (MFC)

Updated articles

• Connection maps - Corrected parameter description of pRefCount in AfxConnection(Un)Advise.
• CSimpleStringT Class - Updated code example.
• MFC class hierarchy chart - Updated MFC hierarchy chart.

C language

New articles

• Generic selection (C11).

Updated articles

• register storage-class specifier - Added C5033 warning.
• C Pragmas - Added system_header pragma documentation.
• C Bit Fields - Clarified example & documented that MSVC doesn't straddle bit-fields.

C runtime library

Updated articles

• _iob - Clarified value of _IOB_ENTRIES across VS versions.
• _snprintf_s, _snprintf_s_l, _snwprintf_s, _snwprintf_s_l - Summarized behavior for argument value combinations.
• snprintf, _snprintf, _snprintf_l, _snwprintf, _snwprintf_l - Summarized behavior for argument value combinations.
• vsnprintf_s, _vsnprintf_s, _vsnprintf_s_l, _vsnwprintf_s, _vsnwprintf_s_l - Summarized behavior for argument value combinations.
• vsnprintf, _vsnprintf, _vsnprintf_l, _vsnwprintf, _vsnwprintf_l - Summarized behavior for argument value combinations.
• to functions - Fixed code example.
• strerror_s, _strerror_s, _wcserror_s, __wcserror_s - Clarified behavior.
• strerror, _strerror, _wcserror, __wcserror - Clarified behavior.
• _stat, _stat32, _stat64, _stati64, _stat32i64, _stat64i32, _wstat, _wstat32, _wstat64, _wstati64, _wstat32i64, _wstat64i32 - Called out changes to _stat family of functions across versions of Visual Studio.

C/C++ compiler intrinsics and assembly language

Updated articles

• __umulh - Updated the code example.

C/C++ in Visual Studio overview

Updated articles

• C++ Conformance improvements, behavior changes, and bug fixes in Visual Studio 2022 - Added 17.6 conformance info.

C/C++ projects and build systems

New articles

• /jumptablerdata (put switch case jump tables in .rdata).

Updated articles

• Advanced Property Page - Updates regarding managed projects that target .NET Framework versus .NET.
• /openmp (Enable OpenMP Support) - Added supported versions.
• Create a C++ console app project - Updated for current version of Visual Studio.
• Build and run a C++ console app project - Updated steps to accommodate Visual Studio version differences regarding the location of the debug folder.
• /ZW (Windows Runtime Compilation) - Added a note about an incompatibility.
• Configure and build with CMake Presets in Visual Studio - Updated supported CMake and CMakePresets.json versions.
• /Zc:lambda (Enable updated lambda processor) - Added note that /permissive- implies /Zc:lambda.
• C/C++ Property Pages - Added description for C language and building ISO standard library modules properties.
• Overview of ARM64 ABI conventions - Clarified terminology regarding register volatility.

C++ in Visual Studio

New articles

• Visual Studio Tools for Unreal Engine overview
• Install Visual Studio Tools for Unreal Engine
• Quickstart: Visual Studio Tools for Unreal Engine

Updated articles

• Overview of modules in C++ - Add description for building ISO standard library modules.
• Compiler Limits - Updated Parameters in macro definition limits.
• How to: Create and Use shared_ptr instances - Added a code example.
• Tutorial: Import the C++ standard library using modules from the command line - Added a description for building ISO standard library modules.
• type_info Class - Marked raw_name Microsoft-specific.

C++ porting and upgrade guide

Updated articles

• Microsoft C/C++ change history 2003 - 2015- Noted changes to _stat family of functions behavior.

C++ Standard Template Library (STL) reference

Updated articles

• basic_string Class - Marked _Copy_s Microsoft-specific.

Code quality

New articles

• Warning C26831
• Warning C26832
• Warning C26833
• Warning C26835

Updated articles

• Use the C++ Core Guidelines checkers - No longer suggest turning off annotation processing for CppCoreChecks.

Clarified behavior for the following warnings:

• Warning C6011, Warning C6200
• Warning C26437, Warning C26439
• Warning C26441, Warning C26444
• Warning C26449, Warning C26450
• Warning C26451, Warning C26452
• Warning C26453, Warning C26454
• Warning C26455, Warning C26494
• Warning C26495, Warning C26498
• Warning C26800, Warning C26810
• Warning C26811, Warning C26813
• Warning C26815, Warning C26816
• Warning C26819, Warning C26827
• Warning C26828, Warning C28196
• Warning C28306, Warning C28307
• Warning C33010

Cross platform development

Updated articles

• Build an OpenGL ES application on Android and iOS - Updated documentation to reflect removal of OpenGL.

Overview of Windows programming in C++

Updated articles

• Microsoft Visual C++ Redistributable latest supported downloads - Noted that VS 2012 reached end of extended support and clarified that the Visual C++ Redistributable for Visual Studio 2015-2022 doesn't have separate packages for different languages.

Community contributors

The following people contributed to the C++, C, and Assembler docs during this period. Thank you! See our contributor guide if you'd like to learn how to contribute.

• moonlit-melody - melody
• AlexGuteniev - Alex Guteniev
• MAP233224 - MAP
• Alice2O3 -
• bearerer -
• bryangalindo - Bryan Galindo
• enricosebastian - Enrico Sebastian
• fsb4000 - Igor Zhukov
• Passw -
• stephen9357 -

What's new history

This section lists major changes to the Microsoft C++ docs February 2023 through May 2023. These changes correspond approximately to Visual Studio version 17.6.

For what's new related to C++ in Visual Studio, see What's new for C++ in Visual Studio.

C runtime library

Updated articles

• fopen_s, _wfopen_s - Clarified some mode modifier flag behaviors.
• fopen, _wfopen - Clarified some mode modifier flag behaviors.
• _fsopen, _wfsopen - Clarified some mode modifier flag behaviors.
• setlocale, _wsetlocale - Clarified behavior for invalid arguments.
• _getch, _getwch - Removed statement that the function can't read Ctrl+C.
• sprintf, _sprintf_l, swprintf, _swprintf, _swprintf_l, __swprintf_l - Documented _swprintf and how _CRT_NON_CONFORMING_SWPRINTFS maps calls to swprintf to _swprintf.
• strtok, _strtok_l, wcstok, _wcstok_l, _mbstok, _mbstok_l - Noted the nonstandard wcstok() and how to call it.
• wcstombs, _wcstombs_l - Added note about UTF-8 support.
• fma, fmaf, fmal - Corrected the documentation for fmaf.

C/C++ compiler and tools errors and warnings

New articles

• Compiler error C7688.
• Compiler warning (level 1, error, off) C5262.
• Compiler warnings (level 1) C5301 and C5302.

Updated articles

• Compiler Warnings by compiler version - Updated with changes for VS 17.5.
• Compiler warnings C4800 through C5999 - Updated with changes for VS 17.5.

C/C++ compiler intrinsics and assembly language

C/C++ in Visual Studio overview

Updated articles

• C++ Conformance improvements, behavior changes, and bug fixes in Visual Studio 2022 - Updated for VS 17.5 changes.
• Microsoft C/C++ language conformance by Visual Studio version - Update with changes for VS 17.5.
• What's new for C++ in Visual Studio 2022 - Update with changes for VS 17.5.

C/C++ preprocessor reference

Updated articles

• Predefined macros - Update _MSC_VER values for 17.3, 17.4, and 17.5.
• Compiler warnings that are off by default - Update with changes for VS 17.5.

C/C++ projects and build systems

Updated articles

• Use the Microsoft C++ toolset from the command line - Improved command-line instructions.
• Walkthrough: Compiling a C++/CLI Program on the Command Line - Improved command-line instructions.
• Walkthrough: Compiling a C++/CX Program on the Command Line - Improved dev command line instructions.
• /Gs (Control stack checking calls) - Updated max value for /Gs.
• Overview of ARM64 ABI conventions - Corrected HFA return values.
• ARM64 exception handling - In the compressed format, PAC is identified by CR=2, not 3.
• Reference: vcperf commands - Updated which commands require administrative privileges.

C++ in Visual Studio

Updated articles

• Transporting exceptions between threads - fix section about types of exception handling.
• Tutorial: Import the C++ standard library using modules from the command line - Updated wording and fixed problems with the path and suggested directory location.

C++ in Visual Studio tutorials

Updated articles

• Create a console calculator in C++ - updated screenshots and updated the result and exception error format.

C++ Standard Template Library (STL) reference

Updated articles

• directory_iterator class - remove experimental.

Code quality

New articles

• Walkthrough: Use Address Sanitizer Continue On Error to find memory safety issues
• Warning C6030
• Warning C6065

Updated articles

• Warning C6001 - Added examples explaining initialization heuristics for C6001.
• Best practices and examples (SAL) - fix SAL annotation.
• Warning C26441 - Clarified example.
• Warning C28213 - Clarified example.
• Warning C6029 - Updated description.
• Warning C6064 - Clarified example.
• Warning C6101 - Clarified text.
• Warning C6217 - Clarified text.

Linux with C++ in Visual Studio

Updated articles

• Connect to your target Linux system in Visual Studio - Added note regarding ssh-keygen.

Overview of Windows programming in C++

Updated articles

• Microsoft Visual C++ Redistributable latest supported downloads - explained why there aren't version numbers listed for VS 2015-2022.

Read and write code using C++ in Visual Studio

Updated articles

• Add a class from an ActiveX control - Clarified which project types the wizard applies to.
• Walkthrough: Working with Projects and Solutions (C++) - Updated for Visual Studio 17.5.

STL/CLR library reference

Updated articles

• queue (STL/CLR) - fixed compilation error in code examples.

Community contributors

The following people contributed to the C++, C, and Assembler docs during this period. Thank you! The following people contributed to the C++, C, and Assembler docs during this period. Thank you! See our contributor guide if you'd like to learn how to contribute.

• fsb4000 - Igor Zhukov
• fjh1997 - FunnyBiu
• X0RW3LL -
• EddieBreeveld - Edward Breeveld
• fkelava - Fran 'peppy' Kelava
• JustaSimpleUser - Centurion Maximus
• lkundrak - Lubomir Rintel
• LuShuchen -
• martinschonger - Martin Schonger
• matbech - Mathias Berchtold
• NADIRHUSSAIN11 - Nadir Hussain
• peanutsjamjam - Atsushi SUGAWARA
• RAJU2529 - VARADHARAJAN K
• robert-andrzejuk - Robert Andrzejuk
• science-enthusiast - Hari
• terrymah - Terry Mahaffey
• vtjnash - Jameson Nash
• XuhuaHuang - XuhuaHuang
• YoniFeng - Yoni Feng