So I suspect a difference in the C library used.

It's my understanding from the comments here that SP 5.40.0.1 switched from using a compiler that uses MSVCRT to one using to UCRT (such as Visual Studio 2022 and mingw-w64 ports of gcc-13.2.0).

In reply to Re^2: [Win32] Weird behavioural change between 5.38.0 and 5.40.0 by ikegami
in thread [Win32] Weird behavioural change between 5.38.0 and 5.40.0 by syphilis

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