Structures and casting in C

Question

I was wondering:

If I have structure definitions, for example, like this:

struct Base {
  int foo;
};

struct Derived {
  int foo; // int foo is comm         


        

Answer 1

You should do

struct Base {
  int foo;
};

struct Derived {
  struct Base base;
  char *bar;
};

to avoid breaking strict aliasing; it is a common misconception that C allows arbitrary casts of pointer types: although it will work as expected in most implementations, it's non-standard.

This also avoids any alignment incompatibilities due to usage of pragma directives.