clumsy cast in dlopen.3

[Bruno Haible <bruno@clisp.org>]

The dlopen.3 man page contains this text:

                  *(void **) &cosine = dlsym(handle, "cos");

              This (clumsy) cast conforms with the ISO C standard and will
              avoid any compiler warnings.

However, such a cast violates the strict aliasing rules of ISO C, no?

The proper workaround is to use a union:

  union { double (*cosine) (double); void *pointer; } u;

  u.pointer = dlsym(handle, "cos");
  ...
  printf("%f\n", u.cosine(2.0));

Bruno