For those 2-3 people still searching for this thing, it’s the old ‘free’ CLI C++ compiler from Visual Studio .NET 2003.

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.3052 for 80×86
Copyright (C) Microsoft Corporation 1984-2002. All rights reserved.

Although Visual C++ .NET 2003 SP1 gives you a later version of the compiler…

Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.6030 for 80×86
Copyright (C) Microsoft Corporation 1984-2002. All rights reserved.

I’m not sure if you can service pack this toolkit.

You can download it from my site as VCToolkitSetup.exe

For anyone who wants to run this under newer versions of Windows as I know I can’t install it on Windows 8 or 10, I installed it on my Windows XP x64 machine, and uploaded it here as vc2003toolkit.7z

By the time this came out, Microsoft had started to admit that they had lost serious ground to GCC, as for years they had neglected the low end $99 market that they had dominated during their fights with Borland in the QuickC vs TurboC days.  Once Borland had withdrawn from the market, Microsoft felt no need to compete and this left plenty of time for GNU tools to take hold in the marketplace.  This was a stopgap reaction as a prelude to the Visual Studio Express that would happen in 2005 onward.

Elsewhere I’ve been able to find an old Windows 2003 SP1 Platform SDK image, it should certainly let this compiler build far more interesting things.  Although unless you really need 2003, you really ought to look at newer stuff.  Unless you like really old stuff, then as a reminder the Win32s 1.1 SDK includes the version 8.00 compiler from 1993 as well.  You can download it from here: win32s-1.1-build-88-msvc32sdev.7z