Introduction

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

Executables built with VS2019 (Toolset v142) do not normally run on Windows XP SP-3. That is because the executables created by VS2019 (Toolset v142) depend on certain functions in KERNEL32.DLL that simply did not exist in Windows XP SP-3 yet. Consequently, the executable will 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 SP-3. This is achieved by substituting the call to the original (missing) function in KERNEL32.DLL with a small "shim" function that is linked directly into the executable. The "shim" function will forward the call to an adequate function in KERNEL32.DLL that does exist on Windows XP SP-3. In fact, there currently are two such function dependencies that must be substituted by CompatLib, i.e. InitializeCriticalSectionEx() and LCMapStringEx().

Note: It still is necessary to install "Service Pack 3" for Windows XP 😏

Usage

In order to build an executable that will run on Windows XP SP-3, the following project settings are required:

1. The runtime library must be set to Multi-threaded (/MT) – static linking is necessary

2. The minimum required version must be set to 5.1 (32-Bit) or 5.2 (64-Bit)

3. The matching variant of libcompat.lib must be added to the 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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