Bad version number checks

Raymond

Version numbers. Very important. And so many people check them wrong.

This is why Windows 95’s GetVersion function returned 3.95 instead of 4.0.
A lot of code checked the version number like this:

  UINT Ver = GetVersion();
  UINT MajorVersion = LOBYTE(uVer);
  UINT MinorVersion = HIBYTE(uVer);
  if (MajorVersion < 3 || MinorVersion < 10) {
   Error("This program requires Windows 3.1");
  }

Now consider what happens when the version number is reported
as 4.0. The major version check passes, but the minor version
check fails since 0 is less than 10.

This bug was so rife that we gave up shimming every app that
had the problem and just decided, “Fine. If anybody asks,
say that the Windows version is 3.95.”

I suspect this is also

why DirectX always reports its version as 4.x.

Raymond Chen

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