Why C++ functions cannot be linked directly by C programs without extern "C":
To support function overloading, the C++ compiler encodes parameter types into the compiled symbol name (e.g. void Print(int) becomes _Z5Printi in Itanium ABI or ?Print@@YAXH@Z in MSVC).
Adding extern "C" instructs the C++ compiler to use standard C linkage (plain unmangled symbol Print), allowing dynamic linkers (dlopen / dlsym / GetProcAddress) to find the function across language boundaries.