Function Pointer assignment works in C but not C++

Question

I need to dynamically link to a library function at runtime in Mac OS X. Following Apple's example, I declare a function pointer and assign it with the result of dlsym(). The following example compiles successfully as a plain C (.c) file. But I need this in a C++ file, and if I compile this example as a C++ file (.cpp), the clang compiler tells me

Cannot initialize a variable of type 'void ()(char *)' with an rvalue of type 'void '

Why does it work in plain 'C', and how can I fix this?

#include <dlfcn.h>

void Test() {
    // Load the library which defines myFunc
    void* lib_handle = dlopen("myLib.dylib", RTLD_LOCAL|RTLD_LAZY);

    // The following line is an error if compiled as C++
    void (*myFunc)(char*) = dlsym(lib_handle, "myFunc");

    myFunc("Hello");

    dlclose(lib_handle) ;
}

Answer 1

dlsym returns void*. In POSIX (but not standard C, as James points out) there's an implicit conversion from void* to a pointer-to-function type, so the assignment to myFunc just works. In C++ there is no implicit conversion (because it's not type safe), so you need to tell the compiler that you really mean it by adding a cast:

void (*myFunc)(char*) = (void(*)(char*))dlsym(lib_handle, "myFunc");

(or you can get fancy with a reinterpret_cast).