xrv3ovl / CompatLib

Compatibility library for re-establishing Windows XP SP-3 support in VS2019

Introduction

CompatLib – compatibility library for re-establishing Windows XP (SP-3) support in VS2019 and VS2022.

C/C++ executables built with VS2019 (Toolset v142) or VS2022 (Toolset v143) do not normally run on Windows XP. That is because the executables created by VS2019 (Toolset v142) or VS2022 (Toolset v143) depend on certain functions in the KERNEL32.DLL system library that simply did not exist in Windows XP yet. Consequently, on the Windows XP system, those executable fail to start with an error message about the missing entry point!

CompatLib provides a workaround for the problem, by eliminating the "problematic" KERNEL32.DLL dependencies from the executable, so that the executable will again be able to run on Windows XP. This is achieved by substituting the call to the original (missing) function in KERNEL32.DLL with a small "shim" function. The "shim" function is linked directly into the executable file; it tries to emulate the call, by forwarding the call to an adequate function in KERNEL32.DLL that does exist on Windows XP. Dependencies that must be substituted by CompatLib include InitializeCriticalSectionEx(), LCMapStringEx(), CompareStringEx() and GetLocaleInfoEx().

Remarks

• Even with CompatLib, it still is necessary to install "Service Pack 3" for Windows XP on the target system

• Running x64 (64-Bit) executables is possible, but requires the Windows XP Professional x64 Edition

• If your application code uses other Win32 API functions unavailable in Windows XP, then CompatLib will not help!
  CompatLib only removes the "problematic" dependencies induced by Microsoft's C/C++ Runtime.

Usage

In order to build an executable that will run on Windows XP with VS2019 (Toolset v142) or VS2022 (Toolset v143), the following settings are required in your Visual Studio C/C++ project:

1. Code Generation / Runtime Library must be set to Multi-threaded (/MT) ➟ static linking is necessary!

2. System / Minimum Required Version must be forced to 5.1 (x86) or 5.2 (x64)

3. Finally, the matching variant of libcompat.lib must be added to Input / Additional Dependencies

License

This work has been released under the CC0 1.0 Universal license.

For details, please refer to:
https://creativecommons.org/publicdomain/zero/1.0/legalcode

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