Compiling under VS2022
Note:Sorry that this article is a bit of a stub! I wanted to make sure it at least existed for those looking to use a modern compiler with the 2013 SDK. It is absolutely reasonable to use the latest compilers with the SDK! I would suggest using the diffs from the two GitHub repos linked on this page for figuring it out for your mod.
With Visual Studio 2013 being out of support, and harder to obtain, there is a lot of pressure to use a newer version of Visual Studio when working with Source SDK 2013. However, as the codebase does not support the changes brought about by later toolset versions, some work is required to get it functioning.
This article is primarily based on these two GitHub repos:
- https://github.com/Source-SDK-Resources/source-sdk-vs2022
- https://github.com/SCell555/Source-PlusPlus
If necessary, these changes can also be made to work with VS2015—VS2019 by changing $PlatformToolset in source_win32_base.vpc.
I'm starting from scratch!
If you don't want to deal with setting up the project, or if you have problems compiling the source code because of certain errors, you can clone this repo since it's based on the official 
Source 2013 repo with minimal changes to allow it to run without problems. Please disregard any "compile process successful but file not found" warning as it is meaningless.
Using 
Mapbase
Mapbase can be compiled with any version of Visual Studio, from 2013-2022. You can toggle support by editing 
\vpc_scripts\newer_vs_toolsets.vpc
Editing Existing Code
If you need to edit an existing codebase (Such as the version of Source 2013 Valve provides on GitHub), you will need to edit or replace certain files.
Running VPC
If you don't have Visual Studio 2013 on your computer, VPC will fail to run, as it can't find registry keys specific to older versions.
You can:
- Grab an edit of VPC that works for modern versions of Visual Studio, such as this one
- Add the registry keys VPC is looking for. See here.
Once ran, the generated VPC scripts will need to be modified to support the newer toolsets.
Fixing particles.lib
Once everything's compiling, you'll hit a snag with particles.lib. It defines the symbol _hypot, and when using VS 2022, that symbol is already being used.
The best solution for this is to go grab an edit of particles.lib that's been fixed. (Like this one)
If you're not a fan of that idea, one alternative could be telling VPC to allow multiple symbols to exist for the client project. This is not a great practice though! Example
Fixing memoverride.cpp
The main file that needs to be fixed for Source to work under VS 2022 is 
memoverride.cpp. Replace it with this one.
In Recap
Do what this page asks you to do while ignoring any reference to Visual Studio 2013, fix the Registry keys problem with the fix from the same page, download particles.lib to <mp or sp>\src\lib\public from this, and finally, replace memoverride.cpp located at <mp or sp>\src\public\tier0 with this one. Have fun making Source mods with updated software ;)