Thanks for the detail! I did manage to see different values for &printf with DLLs on Windows. I was inspired by a long-ago port of a codebase to a newer Visual

Thanks for the detail! I did manage to see different values for &printf with DLLs on Windows. I was inspired by a long-ago port of a codebase to a newer Visual C++; the third-party binary DLLs kept importing the old C runtime and using its malloc/free, which complicated things. I put a __declspec(dllexport) on everything in my header file then (abridged): C:\Users\andrew\Desktop\winlink>cl /LD first.c Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27035 for x64 Copyright (C) Microsoft Corporation. All rights reserved. /out:first.dll /dll /implib:first.lib first.obj Creating library first.lib and object first.exp C:\Users\andrew\Desktop\winlink>cl /LD second.c C:\Users\andrew\Desktop\winlink>cl third.c first.lib second.lib C:\Users\andrew\Desktop\winlink>third.exe 00007FFE38411080 00007FFE38411080 00007FFE382F1080 00007FFE382F1080 hello world 1 hello world 2 If I statically link the three modules together on Windows, then I don't see the different pointers.